EXHIBIT 1.1


                          _________________ Shares/1/

   
                               Lightbridge, Inc.

                                  Common Stock

                             UNDERWRITING AGREEMENT
                             ----------------------
                                                             _____________, 1996
COWEN & COMPANY
Montgomery Securities
Prudential Securities Incorporated
     As Representatives of the Several Underwriters

c/o Cowen & Company
      Financial Square
      New York, New York 10005

 Dear Sirs:

          1.   Introductory.   Lightbridge, Inc., a Delaware corporation (the
               ------------                                                  
"Company"), and certain stockholders of the Company named in Schedule B hereto
(the "Selling Stockholders") propose to sell, pursuant to the terms of this
Agreement, to the several underwriters named in Schedule A hereto (the
"Underwriters," or, each, an "Underwriter"), an aggregate of ______________
shares of Common Stock, $.01 par value (the "Common Stock") of the Company, of
which __________ shares will be sold by the Company and __________ shares will
be sold by the Selling Stockholders.  The aggregate of ______________ shares so
proposed to be sold is hereinafter referred to as the "Firm Stock." The
respective amounts of the Firm Stock to be so purchased by the several
Underwriters are set forth opposite their names in Schedule A hereto, and the
respective amounts to be sold by the Selling Stockholders are set forth opposite
their names in Schedule B hereto.  The Company and the Selling Stockholders also
have granted to the Underwriters, upon the terms and conditions set forth in
Section 3 hereof, up to an additional ______________ shares of Common Stock (the
"Optional Stock"). The Firm Stock and the Optional Stock are hereinafter
collectively referred to as the "Stock."  Cowen & Company ("Cowen"), Montgomery
Securities and Prudential Securities Incorporated are acting as representatives
of the several Underwriters and in such capacity are hereinafter referred to as
the "Representatives."


_______________________

/(1)/  Plus an option to purchase up to ______________ additional shares from
       the Company to cover over-allotments. 

 
                                     - 2 -




          2.      (a) Representations and Warranties of the Company.  The 
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Company represents and warrants to, and agrees with, the several Underwriters
that:

          (i)     A registration statement on Form S-1 (File No. 333-__________)
         in the form in which it became or becomes effective and also in such
         form as it may be when any post-effective amendment thereto shall
         become effective with respect to the Stock, including any preeffective
         prospectuses included as part of the registration statement as
         originally filed or as part of any amendment or supplement thereto, or
         filed pursuant to Rule 424 under the Securities Act of 1933, as amended
         (the "Securities Act"), and the rules and regulations (the "Rules and
         Regulations") of the Securities and Exchange Commission (the
         "Commission") thereunder, copies of which have heretofore been
         delivered to you, has been carefully prepared by the Company in
         conformity with the requirements of the Securities Act and has been
         filed with the Commission under the Securities Act; one or more
         amendments to such registration statement, including in each case an
         amended preeffective prospectus, copies of which amendments have
         heretofore been delivered to you, have been so prepared and filed. If
         it is contemplated, at the time this Agreement is executed, that a 
         post-effective amendment to the registration statement will be filed 
         and must be declared effective before the offering of the Stock may
         commence, the term "Registration Statement" as used in this Agreement
         means the registration statement as amended by said post-effective
         amendment. The term "Registration Statement" as used in this Agreement
         shall also include any registration statement relating to the Stock
         that is filed and declared effective pursuant to Rule 462(b) under the
         Securities Act. All copies of Registration Statements that have been
         delivered to you are identical to the electronically transmitted copies
         thereof filed with the Commission pursuant to the Commission's
         Electronic Data Gathering, Analysis and Retrieval System ("EDGAR"),
         except to the extent permitted by Regulation S-T. The term "Prospectus"
         as used in this Agreement means the prospectus in the form included in
         the Registration Statement, or, (A) if the prospectus included in the
         Registration Statement omits information in reliance on Rule 430A under
         the Securities Act and such information is included in a prospectus
         filed with the Commission pursuant to Rule 424(b) under the Securities
         Act, the term "Prospectus" as used in this Agreement means the
         prospectus in the form included in the Registration Statement as
         supplemented by the addition of the Rule 430A information contained in
         the prospectus filed with the Commission pursuant to Rule 424 (b) and
         (B) if prospectuses that meet the requirements of Section 10(a) of the
         Securities Act are delivered pursuant to Rule 434 under the Securities
         Act, then (i) the term "Prospectus" as used in this Agreement means the
         "prospectus subject to completion" (as such term is defined in Rule 434
         (g) under the Securities Act) as supplemented by (a) the addition of
         Rule 430A information or other information contained in the form of
         prospectus delivered pursuant to Rule 434 (b) (2) under the Securities
         Act or (b) the information contained in the term sheets described in
         Rule 434 (b) (3) under the Securities Act, and (ii) the date of such
         prospectuses shall be deemed to be the date of the term sheets. The
         term "Preeffective Prospectus" as used in this Agreement means the
         prospectus subject 

 
                                     - 3 -

         to completion in the form included in the Registration Statement at the
         time of the initial filing of the Registration Statement with the
         Commission, and as such prospectus shall have been amended from time to
         time prior to the date of the Prospectus. For purposes of this
         Agreement, all references to the Registration Statement, any Pre-
         effective Prospectus, the Prospectus, or any amendment or supplement to
         any of the foregoing shall be deemed to include the respective copies
         thereof filed with the Commission pursuant to EDGAR.

          (ii)    The Commission has not issued or threatened to issue any order
         preventing or suspending the use of any Preeffective Prospectus, and,
         at its date of issue, each Preeffective Prospectus conformed in all
         material respects with the requirements of the Securities Act and did
         not include any untrue statement of a material fact or omit to state a
         material fact required to be stated therein or necessary to make the
         statements therein, in light of the circumstances under which they were
         made, not misleading; and, when the Registration Statement becomes
         effective and at all times subsequent thereto up to and including the
         Closing Dates, the Registration Statement and the Prospectus and any
         amendments or supplements thereto contained and will contain all
         material statements and information required to be included therein by
         the Securities Act at the time of the filing thereof and conformed and
         will conform in all material respects to the requirements of the
         Securities Act and neither the Registration Statement nor the
         Prospectus, nor any amendment or supplement thereto, included or will
         include any untrue statement of a material fact or omitted or will omit
         to state any material fact required to be stated therein or necessary
         to make the statements therein, in light of the circumstances under
         which they were made, not misleading; provided, however, that the
                                               --------  -------
         foregoing representations, warranties and agreements shall not apply to
         information contained in or omitted from any Preeffective Prospectus or
         the Registration Statement or the Prospectus or any such amendment or
         supplement thereto in reliance upon, and in conformity with, written
         information furnished to the Company by or on behalf of any
         Underwriter, directly or through you (or by any Selling Stockholder),
         specifically for use in the preparation thereof; there is no franchise,
         lease, contract, agreement or document required to be described in the
         Registration Statement or Prospectus or to be filed as an exhibit to
         the Registration Statement which is not described or filed therein as
         required; and all descriptions of any such franchises, leases,
         contracts, agreements or documents contained in the Registration
         Statement are accurate descriptions of such documents in all material
         respects.

          (iii)   Subsequent to the respective dates as of which information is
         given in the Registration Statement and Prospectus, and except as set
         forth or contemplated in the Prospectus, the Company has not incurred
         any liabilities or obligations, direct or contingent, nor entered into
         any transactions not in the ordinary course of business, and there has
         not been any material adverse change in the condition (financial or
         otherwise), properties, business, management, net worth or results of
         operations of the Company, or any change in the capital stock, or any
         material change in the short-term or long-term debt of the Company.

 
                                     - 4 -

          (iv)    The financial statements, together with the related notes, set
         forth in the Prospectus and elsewhere in the Registration Statement
         fairly present, on the basis stated in the Registration Statement, the
         financial position and the results of operations and changes in
         financial position of the Company at the respective dates or for the
         respective periods therein specified. Such statements and related notes
         and schedules have been prepared in accordance with generally accepted
         accounting principles applied on a consistent basis except as may be
         set forth in the Prospectus. The selected financial and statistical
         data set forth in the Prospectus under the caption "Selected Financial
         and Other Operating Data" fairly present, on the basis stated in the
         Registration Statement, the information set forth therein.

          (v)     Deloitte & Touche LLP, who have expressed their opinions on
         the audited financial statements and related schedules included in the
         Registration Statement and the Prospectus are independent public
         accountants as required by the Securities Act and the Rules and
         Regulations.

          (vi)    The Company has been duly organized and is validly existing
         and in good standing as a corporation under the laws of its
         jurisdiction of organization, with power and authority (corporate and
         other) to own or lease its business as described in the Prospectus; the
         Company is in possession of and operating in material compliance with
         all franchises, grants, authorizations, licenses, permits, easements,
         consents, certificates and orders required for the conduct of its
         business, all of which are valid and in full force and effect; and the
         Company is duly qualified to do business and in good standing as a
         foreign corporation in all other jurisdictions where its ownership or
         leasing of properties or the conduct of its business requires such
         qualification. The Company has all requisite power and authority, and
         all necessary consents, approvals, authorizations, orders,
         registrations, qualifications, licenses and permits of and from all
         public regulatory or governmental agencies and bodies to own, lease and
         operate its properties and conduct its business as now being conducted
         and as described in the Registration Statement and the Prospectus, and
         no such consent, approval, authorization, order, registration,
         qualification, license or permit contains a materially burdensome
         restriction not adequately disclosed in the Registration Statement and
         the Prospectus. The Company does not own or control, directly or
         indirectly, any corporation, association or other entity.

          (vii)   The Company's authorized and outstanding capital stock is on
         the date hereof, and will be on the Closing Date, as set forth under
         the heading "Capitalization" in the Prospectus; the outstanding shares
         of capital stock (including the outstanding shares of Stock) of the
         Company conform to the description thereof in the Prospectus and have
         been duly authorized and validly issued and are fully paid and
         nonassessable, are duly listed on the Nasdaq National Market and have
         been issued in compliance with all federal and state securities

 
                                     - 5 -

         laws and were not issued in violation of or subject to any preemptive
         rights or similar rights to subscribe for or purchase securities and
         conform to the description thereof contained in the Prospectus. Except
         as disclosed in and or contemplated by the Prospectus and the financial
         statements of the Company and related notes thereto included in the
         Prospectus, the Company does not have outstanding any options or
         warrants to purchase, or any preemptive rights or other rights to
         subscribe for or to purchase any securities or obligations convertible
         into, or any contracts or commitments to issue or sell, shares of its
         capital stock or any such options, rights, convertible securities or
         obligations, except for options granted subsequent to the date of
         information provided in the Prospectus pursuant to the Company's
         employee and stock option plans as disclosed in the Prospectus. The
         description of the Company' s stock option and other stock plans or
         arrangements, and the options or other rights granted or exercised
         thereunder, as set forth in the Prospectus, accurately and fairly
         presents the information required to be shown with respect to such
         plans, arrangements, options and rights.

          (viii)  The Stock to be issued and sold by the Company to the
         Underwriters hereunder has been duly and validly authorized and, when
         issued and delivered against payment therefor as provided herein, will
         be duly and validly issued, fully paid and nonassessable and free of
         any preemptive or similar rights and will conform to the description
         thereof in the Prospectus.

          (ix)    Except as set forth in the Prospectus, there are no legal or
         governmental proceedings pending to which the Company or any executive
         officers or directors is a party or of which any property of the
         Company or any affiliate is subject, which, if determined adversely to
         the Company or any executive officers or directors, might individually
         or in the aggregate (i) prevent or adversely affect the transactions
         contemplated by this Agreement, (ii) suspend the effectiveness of the
         Registration Statement, (iii) prevent or suspend the use of the
         Preeffective Prospectus in any jurisdiction or (iv) result in a
         material adverse change in the condition (financial or otherwise),
         properties, business, management, net worth or results of operations of
         the Company; and to the best of the Company's knowledge no such
         proceedings are threatened or contemplated against the Company or any
         affiliate by governmental authorities or others. The Company is not a
         party nor subject to the provisions of any material injunction,
         judgment, decree or order of any court, regulatory body or other
         governmental agency or body. The description of the Company's
         litigation under the heading "Legal Proceedings" in the Prospectus is
         true and correct and complies with the Rules and Regulations.

          (x)     The execution, delivery and performance of this Agreement and
         the consummation of the transactions herein contemplated will not
         result in a breach or violation of any of the terms or provisions of or
         constitute a default under any indenture, mortgage, deed of trust, note
         agreement or other material agreement or instrument to which the
         Company is a party or by which it or any of its properties is or may be
         bound, the Certificate of Incorporation, By-laws or other
         organizational 

 
                                     - 6 -

         documents of the Company, or any law, order, rule or regulation of any
         court or governmental agency or body having jurisdiction over the
         Company or any of its properties or will result in the creation of a
         lien.

          (xi)    No consent, approval, authorization or order of any court or
         governmental agency or body is required for the consummation by the
         Company of the transactions contemplated by this Agreement, except such
         as may be required by the National Association of Securities Dealers,
         Inc. (the "NASD") or under the Securities Act or the securities or
         "Blue Sky" laws of any jurisdiction in connection with the purchase and
         distribution of the Stock by the Underwriters.

          (xii)   The Company has the full corporate power and authority to
         enter into this Agreement and to perform its obligations hereunder
         (including to issue, sell and deliver the Stock), and this Agreement
         has been duly and validly authorized, executed and delivered by the
         Company and is a valid and binding obligation of the Company,
         enforceable against the Company in accordance with its terms, except to
         the extent that rights to indemnity and contribution hereunder may be
         limited by federal or state securities laws or the public policy
         underlying such laws.

          (xiii)  The Company is in all material respects in compliance with,
         and conducts its business in material conformity with, all applicable
         federal, state, local and foreign laws, rules and regulations
         (including but not limited to the Foreign Corrupt Practices Act and any
         rules and regulations of the Federal Communications Commission) or any
         court or governmental agency or body and the Company has all permits or
         licenses required thereunder; to the knowledge of the Company,
         otherwise than as set forth in the Registration Statement and the
         Prospectus, no prospective change in any of such federal or state laws,
         rules or regulations has been adopted which, when made effective, would
         have a material adverse effect on the operations of the Company.

          (xiv)   The Company has filed all necessary federal, state, local and
         foreign income, payroll, franchise and other tax returns and have paid
         all taxes shown as due thereon or with respect to any of its
         properties, and there is no tax deficiency that has been, or to the
         knowledge of the Company has been threatened or is likely to be,
         asserted against the Company or any of its properties or assets that
         would adversely affect the financial position, business or operations
         of the Company.

          (xv)    No person or entity has the right to require registration of
         shares of Common Stock or other securities of the Company because of
         the filing or effectiveness of the Registration Statement or otherwise,
         except for persons and entities who have expressly waived such right or
         who have been given proper notice and have failed to exercise such
         right within the time or times required under the terms and conditions
         of such right.

 
                                     - 7 -

          (xvi)   Neither the Company nor any of its officers or directors has
         taken or will take, directly or indirectly, any action designed or
         intended to stabilize or manipulate the price of any security of the
         Company, or which caused or resulted in, or which might in the future
         reasonably be expected to cause or result in, stabilization or
         manipulation of the price of the Common Stock of the Company.

          (xvii)  The Company has provided you with all financial statements 
         since inception to the date hereof that are available to the officers
         of the Company, including financial statements for the three months
         ended December 31, 1995 and the six months ended June 30, 1996.

          (xviii) The Company owns, possesses, or has rights to use all patents,
         trademarks, trademark registrations, service marks, service mark
         registrations, tradenames, copyrights, licenses, inventions, trade
         secrets and rights described in the Prospectus as being owned or used
         by it or necessary for the conduct of its business, and the Company has
         not received notice of any claim to the contrary or any challenge by
         any other person to the rights of the Company with respect to the
         foregoing. The Company's business as now conducted does not and will
         not infringe or conflict with in any material respect patents,
         trademarks, service marks, trade names, copyrights, trade secrets,
         licenses or other intellectual property or franchise right of any
         person. No claim has been made against the Company alleging the
         infringement by the Company of any patent, trademark, service mark,
         tradename, copyright, trade secret, license in or other intellectual
         property right or franchise right of any person.

          (xix)   No breach or default exists in the due performance and 
         observance by the Company of any term, covenant or condition of all
         contracts required by Item 601(b)(10) of Regulation S-K under the
         Securities Act to be filed as exhibits to the Registration Statement.
         To the Company's knowledge, no other party to such contract is in
         material default under or in breach of any such obligations. The
         Company has not received any notice of such default or breach.

          (xx)    The Company is not involved in any labor dispute nor is any 
         such dispute threatened. The Company is not aware that (A) any
         executive, key employee or significant group of employees of the
         Company plans to terminate employment with the Company or (B) any such
         executive or key employee is subject to any noncompete, nondisclosure,
         confidentiality, employment, consulting or similar agreement that would
         be violated by the present or proposed business activities of the
         Company. The Company does not have or expects to have any liability for
         any prohibited transaction or funding deficiency or any complete or
         partial withdrawal liability with respect to any pension, profit
         sharing or other plan which is subject to the Employee Retirement
         Income Security Act of 1974, as amended ("ERISA"), to which the Company
         makes or ever has made a contribution and in which any employee of the
         Company is or has ever been a participant. With respect to such 

 
                                     - 8 -

         plans, the Company is in compliance in all material respects with all
         applicable provisions of ERISA.

          (xxi)   The Company has, and the Company as of the Closing Dates will
         have, good and marketable title in fee simple to all real property and
         good and marketable title to all personal property owned by it which is
         material to the business of the Company, in each case free and clear of
         all liens, encumbrances and defects except such as are described the
         Prospectus or such as would not have a material adverse effect on the
         Company; and any real property and buildings held under lease by the
         Company are, or will be as of the Closing Dates, held by it under
         valid, subsisting and enforceable leases with such exceptions as would
         not have a material adverse effect on the Company, in each case except
         as described in or contemplated by the Prospectus.

          (xxii)  The Company is insured by insurers of financial responsibility
         against such losses and risks and in such amounts as are customary in
         the business in which it is engaged; and no such insurer has notified
         or indicated to the Company that it will not be able to renew its
         existing insurance coverage as and when such coverage expires; and the
         Company has no reason to believe that, if such coverage is not renewed,
         that it will not be able to obtain similar coverage from similar
         insurers as may be necessary to continue its business at a cost that
         would not materially and adversely affect the condition, financial or
         otherwise, or the earnings, business or operations of the Company,
         except as described in or contemplated by the Prospectus.

          (xxiii) Other than as contemplated by this Agreement, there is no
         broker, finder or other party that is entitled to receive from the
         Company any brokerage or finder's fee or other fee or commission as a
         result of any of the transactions contemplated by this Agreement.

          (xxiv)  The Company has complied with all provisions of Section 
         517.0 75 Florida Statutes (Chapter 92-198; Laws of Florida).

          (xxv)   The Company maintains a system of internal accounting controls
         sufficient to provide reasonable assurances that (i) transactions are
         executed in accordance with management's general or specific
         authorization; (ii) transactions are recorded as necessary to permit
         preparation of financial statements in conformity with generally
         accepted accounting principles and to maintain accountability for
         assets; (iii) access to assets is permitted only in accordance with
         management's general or specific authorization; and (iv) the recorded
         accountability for assets is compared with existing assets at
         reasonable intervals and appropriate action is taken with respect to
         any differences.

          (xxvi)  To the Company's knowledge, neither the Company nor any
         employee or agent of the Company has made any payment or received or
         retained any payment 

 
                                     - 9 -

         in violation of any law, rule or regulation, which payment, receipt or
         retention of funds is of a character required to be disclosed in the
         Prospectus.

          (xxvii) The Company is not or will not become an "investment company"
         or an entity "controlled" by an "investment company" as such terms are
         defined in the Investment Company Act of 1940, as amended, after the
         closing of the offering and the application of the proceeds therefrom.

          (xxiii) Each certificate signed by any officer of the Company and
         delivered to the Underwriters or counsel for the Underwriters shall be
         deemed to be a representation and warranty by the Company as to the
         matters covered thereby.

          (xxiv)  The Company has obtained the written agreement described in
         Section 8 (k) of this Agreement from each of its officers, directors
         and holders of Common Stock.

                  (b) Representations and Warranties and Agreements of the
                      ----------------------------------------------------
Selling Stockholders. Each Selling Stockholder represents and warrants to, and
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agrees with, the several Underwriters that such Selling Stockholder:

          (i)     Now has, and on the Closing Dates will have, valid and
         marketable title to the Stock to be sold by such Selling Stockholder,
         free and clear of any lien, claim, security interest or other
         encumbrance, including, without limitation, any restriction on
         transfer, and has full right, power and authority to enter into this
         Agreement, the Power of Attorney and the Custody Agreement (each as
         hereinafter defined), and, to the extent such Selling Stockholder is a
         corporation, has been duly organized and is validly existing and in
         good standing as a corporation under the laws of its jurisdiction of
         organization.

          (ii)    Now has, and on the Closing Dates will have, upon delivery of
         and payment for each share of Stock hereunder, full right, power and
         authority and approval required by law to sell, transfer, assign and
         deliver the Stock being sold by such Selling Stockholder hereunder, and
         each of the several Underwriters will acquire valid and marketable
         title to all of the Stock being sold to the Underwriters by such
         Selling Stockholder, free and clear of any liens, encumbrances,
         equities claims, restrictions on transfer or other defects whatsoever.

          (iii)   For a period of 180 days after the date of this Agreement,
         without the consent of Cowen, such Selling Stockholder will not offer
         to sell, sell, contract to sell or otherwise dispose of any shares of
         Common Stock or securities convertible into or exchangeable for shares
         of Common Stock, including, without limitation shares of Common Stock
         which may be deemed to be beneficially owned by the undersigned in
         accordance with the Rules and Regulations, except for the Stock being
         sold hereunder.

 
                                     - 10 -

          (iv)    Has duly executed and delivered a power of attorney, in
         substantially the form heretofore delivered by the Representatives (the
         "Power of Attorney"), appointing ______________ and ______________, and
         each of them, as attorney-in-fact (the "Attorneys-in-fact") with
         authority to execute and deliver this Agreement on behalf of such
         Selling Stockholder, to authorize the delivery of the shares of Stock
         to be sold by such Selling Stockholder hereunder and otherwise to act
         on behalf of such Selling Stockholder in connection with the
         transactions contemplated by this Agreement.

          (v)     Has duly executed and delivered a custody agreement, in
         substantially the form heretofore delivered by the Representatives (the
         "Custody Agreement"), with the Company as custodian (the "Custodian"),
         pursuant to which certificates in negotiable form for the shares of
         Stock to be sold by such Selling Stockholder hereunder have been placed
         in custody for delivery under this Agreement.

          (vi)    Has, by execution and delivery of each of this Agreement, the
         Power of Attorney and the Custody Agreement, created valid and binding
         obligations of such Selling Stockholder, enforceable against such
         Selling Stockholder in accordance with the terms of such agreements and
         documents, except to the extent that rights to indemnity hereunder may
         be limited by federal or state securities laws or the public policy
         underlying such laws.

          (vii)   The performance of this Agreement, the Custody Agreement and
         the Power of Attorney, and the consummation of the transactions
         contemplated hereby and thereby will not result in a breach or
         violation by such Selling Stockholder of any of the terms or provisions
         of, or constitute a default by such Selling Stockholder under, any
         indenture, mortgage, deed of trust, trust (constructive or other), loan
         agreement, lease, franchise, license or other agreement or instrument
         to which such Selling Stockholder is a party or by which such Selling
         Stockholder or any of its properties is bound, or any judgment of any
         court or governmental agency or body applicable to such Selling
         Stockholder or any of its properties, or to such Selling Stockholder's
         knowledge, any statute, decree, order, rule or regulation of any court
         or governmental agency or body applicable to such Selling Stockholder
         or any of its properties.

          (viii)  Has reviewed the Registration Statement and Prospectus and,
         although such Selling Stockholder has not independently verified the
         accuracy or completeness of all the information contained therein,
         nothing has come to the attention of such Selling Stockholder that
         would lead such Selling Stockholder to believe that on the Effective
         Date, the Registration Statement contained any untrue statement of a
         material fact or omitted to state any material fact required to be
         stated therein or necessary in order to make the statements therein not
         misleading; and, on the Effective Date the Prospectus contained and, on
         the Closing Date and any later date on which Optional Stock is to be
         purchased, contains any untrue statement of a material fact or omitted
         or omits to state any material fact necessary 

 
                                     - 11 -

         in order to make the statements therein, in the light of the
         circumstances under which they were made, not misleading.

         Each Selling Stockholder agrees that the shares of Stock represented by
         the certificates held in custody under the Custody Agreement are for
         the benefit of and coupled with and subject to the interests of the
         Underwriters, the other Selling Stockholders and the Company hereunder,
         and that the arrangement for such custody and the appointment of the
         Attorneys-in-fact are irrevocable; that the obligations of such Selling
         Stockholder hereunder shall not be terminated by operation of law,
         whether by the death or incapacity, liquidation or distribution of such
         Selling Stockholder, or any other event, that if such Selling
         Stockholder should die or become incapacitated or is liquidated or
         dissolved or any other event occurs, before the delivery of the Stock
         hereunder, certificates for the Stock to be sold by such Selling
         Stockholder shall be delivered on behalf of such Selling Stockholder in
         accordance with the terms and conditions of this Agreement and the
         Custody Agreement, and action taken by the Attorneys-in-fact or any of
         them under the Power of Attorney shall be as valid as if such death,
         incapacity, liquidation or dissolution or other event had not occurred,
         whether or not the Custodian, the Attorneys-in-fact or any of them
         shall have notice of such death, incapacity, liquidation or dissolution
         or other event.

          3.      Purchase by, and Sale and Delivery to, Underwriters -- Closing
                  --------------------------------------------------------------
Dates. The Company and the Selling Stockholders agree, severally and not
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jointly, to sell to the Underwriters the Firm Stock with the number of shares to
be sold by the Company and each Selling Shareholder being the number of Shares
set opposite his, her or its name in Schedule B and on the basis of the
representations, warranties, covenants and agreements herein contained, but
subject to the terms and conditions herein set forth, the Underwriters agree,
severally and not jointly, to purchase the Firm Stock from the Company and the
Selling Stockholders, the number of shares of Firm Stock to be purchased by each
Underwriter being set opposite its name in Schedule A, subject to adjustment in
accordance with Section 12 hereof. The number of shares of Stock to be purchased
by each Underwriter from each Selling Stockholder hereunder shall bear the same
proportion to the total number of shares of Stock to be purchased by such
Underwriter hereunder as the number of shares of stock being sold by each
Selling Stockholder bears to the total number o shares of Stock being sold by
all Selling Stockholders, subject to adjustment by the Representatives to
eliminate fractions.

          The purchase price per share to be paid by the Underwriters to the
Company and the Selling Stockholders will be $ _____ per share (the "Purchase
Price").

          The Company and the Selling Stockholders will deliver the Firm Stock
to the Representatives for the respective accounts of the several Underwriters
in the form of definitive certificates, issued in such names and in such
denominations as the Representatives may direct by notice in writing to the
Company given at or prior to 12:00 Noon, New York Time, on the second full
business day preceding the First Closing Date (as defined below) or, if no such
direction is received, in the names of the respective Underwriters or in such
other names as 

 
                                     - 12 -

Cowen may designate (solely for the purpose of administrative convenience) and
in such denominations as Cowen may determine, against payment of the aggregate
Purchase Price therefor by wire transfer (same day funds), payable to the order
of the Company, all at the offices of Foley, Hoag & Eliot, One Post Office
Square, Boston, Massachusetts 02109. The time and date of the delivery and
closing shall be at 10:00 A.M., New York Time, on ___________, 1996, in
accordance with Rule 15c6-1 of the Exchange Act. The time and date of such
payment and delivery are herein referred to as the "First Closing Date". The
Closing Date and the location of delivery of, and the form of payment for, the
Firm Stock may be varied by agreement between the Company and Cowen. The Closing
Date may be postponed pursuant to the provisions of Section 12.

          The Company and the Selling Stockholders shall make the certificates
for the Stock available to the Representatives for examination on behalf of the
Underwriters not later than 10:00 A.M., New York Time, on the business day
preceding the Closing Date at the offices of Cowen & Company, Financial Square,
New York, New York 10005.

          It is understood that Cowen, Montgomery Securities or Prudential
Securities Incorporated, individually and not as Representatives of the several
Underwriters, may (but shall not be obligated to) make payment to the Company on
behalf of any Underwriter or Underwriters, for the Stock to be purchased by such
Underwriter or Underwriters. Any such payment by Cowen, Montgomery Securities or
Prudential Securities Incorporated shall not relieve such Underwriter or
Underwriters from any of its or their other obligations hereunder.

          The several Underwriters agree to make an initial public offering of
the Firm Stock at the initial public offering price as soon after the
effectiveness of the Registration Statement as in their judgment is advisable.
The Representatives shall promptly advise the Company and the Selling
Stockholders of the making of the initial public offering.

          For the purpose of covering any over-allotments in connection with the
distribution and sale of the Firm Stock as contemplated by the Prospectus, the
Company and each of the Selling Stockholders hereby grants to the Underwriters
an option to purchase, severally and not jointly, up to the aggregate number of
shares of Optional Stock set forth opposite the Company's and each such Selling
Stockholder's name on Schedule B hereto, for an aggregate of up to____________ 
shares. The price per share to be paid for the Optional Stock shall be the
Purchase Price. The option granted hereby may be exercised as to all or any part
of the Optional Stock at any time, and from time to time, not more than thirty
(30) days subsequent to the effective date of this Agreement. No Optional Stock
shall be sold and delivered unless the Firm Stock previously has been, or
simultaneously is, sold and delivered. The right to purchase the Optional Stock
or any portion thereof may be surrendered and terminated at any time upon notice
by the Underwriters to the Company and the Selling Stockholders.

          The option granted hereby may be exercised by the Underwriters by
giving written notice from Cowen to the Company and the Selling Stockholders
setting forth the number of shares of the Optional Stock to be purchased by them
and the date and time for delivery of and payment for the Optional Stock. Each
date and time for delivery of and payment 

 
                                     - 13 -

for the Optional Stock (which may be the First Closing Date, but not earlier) is
herein called the "Option Closing Date" and shall in no event be earlier than
two (2) business days nor later than ten (10) business days after written notice
is given. (The Option Closing Date and the First Closing Date are herein called
the "Closing Dates"). All purchases of Optional Stock shall be made first from
the Company and then the Selling Stockholders on a pro rata basis. Optional
Stock shall be purchased for the account of each Underwriter in the same
proportion as the number of shares of Firm Stock set forth opposite such
Underwriter's name in Schedule B hereto bears to the total number of shares of
Firm Stock (subject to adjustment by the Underwriters to eliminate odd lots).
Upon exercise of the option by the Underwriters, the Company and the Selling
Stockholders agree to sell to the Underwriters the number of shares of Optional
Stock set forth in the written notice of exercise and the Underwriters agree,
severally and not jointly and subject to the terms and conditions herein set
forth, to purchase the number of such shares determined as aforesaid.

          The Company and the Selling Stockholders will deliver the Optional
Stock to the Underwriters (in the form of definitive certificates, issued in
such names and in such denominations as the Representatives may direct by notice
in writing to the Company and the Selling Stockholders given at or prior to
12:00 Noon, New York Time, on the second full business day preceding the Option
Closing Date or, if no such direction is received, in the names of the
respective Underwriters or in such other names as Cowen may designate (solely
for the purpose of administrative convenience) and in such denominations as
Cowen may determine, against payment of the aggregate Purchase Price therefor by
wire transfer (same day funds), payable to the order of the Company and the
Company as Custodian for the Selling Stockholders or payable as directed by the
Company and such Custodian all at the offices of Foley, Hoag & Eliot, One Post
Office Square, Boston, Massachusetts 02109. The Company and the Selling
Stockholders shall make the certificates for the Optional Stock available to the
Underwriters for examination not later than 10:00 A.M., New York Time, on the
business day preceding the Option Closing Date at the offices of Cowen &
Company, Financial Square, New York, New York 10005. The Option Closing Date and
the location of delivery of, and the form of payment for, the Option Stock may
be varied by agreement between the Company, the Custodian for the Selling
Stockholders and Cowen. The Option Closing Date may be postponed pursuant to the
provisions of Section 12.

          4.      Covenants and Agreements of the Company. The Company covenants
                  ---------------------------------------
and agrees with the several Underwriters that:

          (a)     The Company will (i) if the Company and the Representatives
     have determined not to proceed pursuant to Rule 430A, use its best efforts
     to cause the Registration Statement to become effective, (ii) if the
     Company and the Representatives have determined to proceed pursuant to Rule
     430A, use its best efforts to comply with the provisions of and make all
     requisite filings with the Commission pursuant to Rule 430A and Rule 424 of
     the Rules and Regulations and (iii) if the Company and the Representatives
     have determined to deliver Prospectuses pursuant to Rule 434 of the Rules
     and Regulations, to use its best efforts to comply with all the applicable
     provisions thereof. The Company will advise the Representatives promptly as
     to the time at which 

 
                                     - 14 -

     the Registration Statement becomes effective, will advise the
     Representatives promptly of the issuance by the Commission of any stop
     order suspending the effectiveness of the Registration Statement or of the
     institution of any proceedings for that purpose, and will use its best
     efforts to prevent the issuance of any such stop order and to obtain as
     soon as possible the lifting thereof, if issued. The Company will advise
     the Representatives promptly of the receipt of any comments of the
     Commission or any request by the Commission for any amendment of or
     supplement to the Registration Statement or the Prospectus or for
     additional information and will not at any time file any amendment to the
     Registration Statement or supplement to the Prospectus which shall not
     previously have been submitted to the Representatives a reasonable time
     prior to the proposed filing thereof or to which the Representatives shall
     not have previously approved in writing (such approval not to be
     unreasonably withheld or delayed) or which is not in compliance with the
     Securities Act and the Rules and Regulations.

          (b)     The Company will prepare and file with the Commission,
     promptly upon the request of the Representatives, any amendments or
     supplements to the Registration Statement or the Prospectus which in the
     opinion of the Representatives may be necessary to enable the several
     Underwriters to continue the distribution of the Stock and will use its
     best efforts to cause the same to become effective as promptly as possible.

          (c)     If at any time after the effective date of the Registration
     Statement when a prospectus relating to the Stock is required to be
     delivered under the Securities Act any event relating to or affecting the
     Company occurs as a result of which the Prospectus or any other prospectus
     as then in effect would include an untrue statement of a material fact, or
     omit to state any material fact necessary to make the statements therein,
     in light of the circumstances under which they were made, not misleading,
     or if it is necessary at any time to amend the Prospectus to comply with
     the Securities Act, the Company will promptly notify the Representatives
     thereof and will prepare an amended or supplemented prospectus which will
     correct such statement or omission; and in case any Underwriter is required
     to deliver a prospectus relating to the Stock nine (9) months or more after
     the effective date of the Registration Statement, the Company upon the
     request of the Representatives and at the expense of such Underwriter will
     prepare promptly such prospectus or prospectuses as may be necessary to
     permit compliance with the requirements of Section 10(a)(3) of the
     Securities Act.

          (d)     The Company will deliver to the Representatives, at or before
     the Closing Dates, signed copies of the Registration Statement, as
     originally filed with the Commission, and all amendments thereto including
     all financial statements and exhibits thereto, and will deliver to the
     Representatives such number of copies of the Registration Statement,
     including such financial statements, but without exhibits, and all
     amendments thereto, as the Representatives may reasonably request. The
     Company will deliver or mail to or upon the order of the Representatives,
     from time to time until the effective date of the Registration Statement,
     as many copies of the Preeffective Prospectus as the Representatives may
     reasonably request. The Company will deliver or mail to or upon the order
     of the Representatives on the date of the initial public offering, and
     thereafter

 
                                     - 15 -

     from time to time during the period when delivery of a prospectus relating
     to the Stock is required under the Securities Act, as many copies of the
     Prospectus, in final form or as thereafter amended or supplemented as the
     Representatives may reasonably request; provided, however, that the expense
                                             --------  -------   
     of the preparation and delivery of any prospectus required for use nine (9)
     months or more after the effective date of the Registration Statement shall
     be borne by the Underwriters required to deliver such prospectus.

          (e)     The Company will make generally available to its Stockholders
     as soon as practicable, but not later than fifteen (15) months after the
     effective date of the Registration Statement, an earnings statement which
     will be in reasonable detail (but which need not be audited) and which will
     comply with Section 11(a) of the Securities Act, covering a period of at
     least twelve (12) months beginning after the "effective date" (as defined
     in Rule 158 under the Securities Act) of the Registration Statement.

          (f)     The Company will cooperate with the Representatives to enable
     the Stock to be registered or qualified for offering and sale by the
     Underwriters and by dealers under the securities laws of such jurisdictions
     as the Representatives may designate, provided that such jurisdictions are
     within the United States, Guam or Puerto Rico, and at the request of the
     Representatives will make such applications and furnish such consents to
     service of process or other documents as may be required of it as the
     issuer of the Stock for that purpose; provided, however, that the Company
                                           --------  -------
     shall not be required to qualify to do business or to file a general
     consent (other than that arising out of the offering or sale of the Stock)
     to service of process in any such jurisdiction where it is not now so
     subject. The Company will, from time to time, prepare and file such
     statements and reports as are or may be required of it as the issuer of the
     Stock to continue such qualifications in effect for so long a period as the
     Representatives may reasonably request for the distribution of the Stock.
     The Company will advise the Representatives promptly after the Company
     becomes aware of the suspension of the qualifications or registration of
     (or any such exception relating to) the Common Stock of the Company for
     offering, sale or trading in any jurisdiction or of any initiation or
     threat of any proceeding for any such purpose, and in the event of the
     issuance of any orders suspending such qualifications, registration or
     exception, the Company will, with the cooperation of the Representatives
     use its best efforts to obtain the withdrawal thereof.

          (g)     The Company will furnish to its stockholders annual reports
     containing financial statements certified by independent public accountants
     and with quarterly summary financial information in reasonable detail which
     may be unaudited. Stockholders.

          (h)     The Company will use its best efforts to list the Stock,
     subject to official notice of issuance, on the Nasdaq National Market.

          (i)     The Company will maintain a transfer agent and registrar for
     its Common Stock.

 
                                     - 16 -

          (j)     Prior to filing its first six quarterly statements on Form 
     10-Q, the Company will have its independent auditors perform a limited
     quarterly review of its quarterly numbers.

          (k)     The Company will not offer, sell, assign, transfer, encumber,
     contract to sell, grant an option to purchase or otherwise dispose of any
     shares of Common Stock or securities convertible into or exercisable or
     exchangeable for Common Stock (including, without limitation, Common Stock
     of the Company which may be deemed to be beneficially owned by the Company
     in accordance with the Rules and Regulations) during the 180 days following
     the date on which the price of the Common Stock to be purchased by the
     Underwriters is set (except with prior written consent of each of the
     Representatives), other than the Company's sale of Common Stock hereunder
     and the Company's issuance of Common Stock upon the exercise of warrants
     and stock options which are presently outstanding and described in the
     Prospectus or pursuant to the Company's stock option plans.

          (l)     The Company will apply the net proceeds from the sale of the
     Stock as set forth in the description under "Use of Proceeds" in the
     Prospectus which description complies in all material respects with the
     requirements of Item 504 of Regulation S-K.

          (m)     The Company will supply you with copies of all correspondence
     to and from, and all documents issued to and by, the Commission in
     connection with the registration of the Stock under the Securities Act and
     the Exchange Act.

          (n)     Prior to the Closing Dates, the Company will furnish to you,
     as soon as they have been prepared, copies of any unaudited interim
     financial statements of the Company for any periods subsequent to the
     periods covered by the financial statements appearing in the Registration
     Statement and the Prospectus.

          (o)     Prior to the First Closing Date, the Company will issue no
     press release or other communications directly or indirectly and hold no
     press conference with respect to the Company, the financial condition,
     results of operation, business, prospects, assets or liabilities of any of
     them, or the offering of the Stock, without your prior written consent. For
     a period of twelve (12) months following the Closing Date, the Company will
     use its best efforts to provide to you copies of each press release or
     other public communications with respect to the financial condition,
     results of operations, business, prospects, assets or liabilities of the
     Company at least twenty-four (24) hours prior to the public issuance
     thereof or such longer advance period as may reasonably be practicable.

          (p)     During the period of five (5) years hereafter, the Company
     will furnish to the Representatives, and upon request of the
     Representatives, to each of the Underwriters: (i) as soon as practicable
     after the end of each fiscal year, copies of the Annual Report of the
     Company containing the balance sheet of the Company as of the close of such
     fiscal year and statements of income, stockholder's equity and cash flows
     for the year then ended and the opinion thereon of the Company's
     independent public accountants; (ii) as 

 
                                     -17-

     soon as practicable after the end of each fiscal year, copies of the Annual
     Report of the Company containing the balance sheet of the Company as of the
     close of such fiscal year and statements of income, stockholder's equity
     and cash flows for the year then ended and the opinion thereon of the
     Company's independent public accountants; (ii) as soon as practicable after
     the filing thereof, copies of each proxy statement, Annual Report on Form
     10-K, Quarterly Report on Form 10-Q, Current Report on Form 8-K or other
     report filed by the Company with the Commission, or the NASD or any
     securities exchange; and (iii) as soon as available, copies of any report
     or communication of the Company mailed generally to holders of its Common
     Stock and (iv) from time to time, such other information concerning the
     Company as you may reasonably request.

          5.   Payment of Expenses.  (a) The Company will pay (directly or by
               -------------------
reimbursement) all costs, fees and expenses incurred in connection with or
incident to the performance of the obligations of the Company and of the Selling
Stockholders under this Agreement and in connection with the transactions
contemplated hereby, including but not limited to (i) all expenses and taxes
incident to the issuance and delivery of the Stock to the Representatives; (ii)
all expenses incident to the registration of the Stock under the Securities Act;
(iii) the costs of preparing stock certificates (including printing and
engraving costs); (iv) all fees and expenses of the registrar and transfer agent
of the Stock; (v) all necessary issue, transfer and other stamp taxes in
connection with the issuance and sale of the Stock to the Underwriters; (vi)
fees and expenses of the Company's counsel and the Company's independent
accountants; (vii) all costs and expenses incurred in connection with the
preparation, printing, filing, shipping and distribution of the Registration
Statement, each Preeffective Prospectus and the Prospectus (including all
exhibits and financial statements) and all amendments and supplements provided
for herein, the Selling Stockholders' Powers of Attorney, the Custody
Agreements, the "Agreement Among Underwriters" between the Representatives and
the Underwriters, the Master Selected Dealers' Agreement, the Underwriters'
Questionnaire and the Blue Sky memoranda and this Agreement; (viii) all filing
fees, attorneys fees' and expenses incurred by the Company or the Underwriters
in connection with exemptions from the qualifying or registering (or obtaining
qualification or registration of) all or any part of the Stock for offer and
sale and determination of its eligibility for investment under the Blue Sky or
other securities laws of such jurisdictions as the Representatives may
designate; (ix) all fees and expenses paid or incurred in connection with
filings made with the NASD; and (x) all other reasonable costs and expenses
incident to the performance of their obligations hereunder which are not
otherwise specifically provided for in this Section.

          (b)  Each Selling Stockholder will pay (directly or by reimbursement)
all fees and expenses incident to the performance of such Selling Stockholder's
obligations under this Agreement which are not otherwise specifically provided
for herein, including but not limited to any fees and expenses of counsel for
such Selling Stockholder, such Selling Stockholder's pro rata share of fees and
expenses of the Attorneys-in-fact and the Custodian and all expenses and taxes
incident to the sale and delivery of the Stock to be sold by such Selling
Stockholder to the Underwriters hereunder.

          (c)  In addition to their other obligations under Section 6(a) hereof,
the Company and the Selling Stockholders agree that, as an interim measure
during the pendency of any claim, action, investigation, inquiry or other
proceeding arising out of or based upon (i) any misstatement or omission or any
alleged misstatement or omission or (ii) any breach or inaccuracy in their
representations and warranties, they will reimburse each Underwriter on a

 
                                      -18-

quarterly basis for all reasonable legal or other expenses incurred in
connection with investigating or defending any such claim, action,
investigation, inquiry or other proceeding, notwithstanding the absence of a
judicial determination as to the propriety and enforceability of the Company's
and Selling Stockholders' obligation to reimburse each Underwriter for such
expenses and the possibility that such payments might later be held to have been
improper by a court of competent jurisdiction. To the extent that any such
interim reimbursement payment is so held to have been improper, each Underwriter
shall promptly return it to the Company or the Selling Stockholder, as the case
maybe, together with interest, compounded daily, determined on the basis of the
prime rate (or other commercial lending rate for borrowers of the highest credit
standing) announced from time to timed by Chemical Bank, New York, New York (the
"Prime Rate"). Any such interim reimbursement payments which are not made to an
Underwriter in a timely manner as provided below shall bear interest at the
Prime Rate from the due date for such reimbursement. This expense reimbursement
agreement will be in addition to any other liability which the Company and the
Selling Stockholders may otherwise have. The request for reimbursement will be
sent to the Company with a copy to each Selling Stockholder. In the event that
the Company fails to make such reimbursement payment within thirty (30) days of
the reimbursement request, the Representatives shall notify the Selling
Stockholders of their obligation to make such reimbursement payments within
fifteen (15) days; provided, however, that each Selling Stockholder shall be
required to advance at such time only its pro rata portion of the reimbursement
payment. To the extent that any Selling Stockholder fails to pay its pro rata
portion in timely response to the Underwriters' request, the other Selling
Stockholders shall be jointly and severally liable for such reimbursement
payment and each shall render such payment to the Representatives within fifteen
(15) days of written demand therefor by the Representatives.

          (d)  In addition to its other obligations under Section 6(b) hereof,
each Underwriter severally agrees that, as an interim measure during the
pendency of any claim, action, investigation, inquiry or other proceeding
arising out of or based upon any misstatement or omission of a material fact, or
any alleged misstatement or omission of a material fact, described in Section
6(b) hereof which relates to information furnished by the Underwriters to the
Company, it will reimburse the Company (and, to the extent applicable, each
officer, director, or controlling person or Selling Stockholder) on a quarterly
basis for all reasonable legal or other expenses incurred in connection with
investigating or defending any such claim, action, investigation, inquiry or
other proceeding, notwithstanding the absence of a judicial determination as to
the propriety and enforceability of the Underwriters' obligation to reimburse
the Company (and, to the extent applicable, each officer, director, or
controlling person or Selling Stockholder) for such expenses and the possibility
that such payments might later be held to have been improper by a court of
competent jurisdiction. To the extent that any such interim reimbursement
payment is so held to have been improper, the Company (and, to the extent
applicable, each officer, director, or controlling person or Selling
Stockholder) shall promptly return it to the Underwriters together with
interest, compounded daily, determined on the basis of the Prime Rate. Any such
interim reimbursement payments which are not made to the Company within thirty
(30) days of a request for reimbursement shall bear interest at the Prime Rate
from the date of such request. This indemnity agreement will be in addition to
any liability which such Underwriter may otherwise have.

 
                                      -19-

          (e)  It is agreed that any controversy arising out of the operation of
the interim reimbursement arrangements set forth in paragraph (c) and/or (d) of
this Section 5, including the amounts of any requested reimbursement payments
and the method of determining such amounts, shall be settled by arbitration
conducted under the provisions of and pursuant to the arbitration procedures of
the American Arbitration Association. Any such arbitration must be commenced by
service of a written demand for arbitration or written notice of intention to
arbitrate, therein electing the arbitration tribunal. In the event the party
demanding arbitration does not make such designation of an arbitration tribunal
in such demand or notice, then the party responding to said demand or notice is
authorized to do so. Such an arbitration would be limited to the operation of
the interim reimbursement provisions contained in paragraph (c) and/or (d) of
this Section 5 and would not resolve the ultimate propriety or enforceability of
the obligation to reimburse expenses which is created by the provisions of
Section 6.

          6.   Indemnification and Contribution.  (a) The Company agrees to
               --------------------------------
indemnify and hold harmless each Underwriter and each person, if any, who
controls such Underwriter within the meaning of the Securities Act and the
respective officers, directors, shareholders, partners and employees of each of
such Underwriter or person who controls such Underwriter (collectively, the
"Underwriter Indemnified Parties" and, each, an "Underwriter Indemnified
Party"), against any losses, claims, damages, liabilities or expenses (including
the reasonable cost of investigating and defending against any claims therefor
and counsel fees incurred in connection therewith) , joint or several, which may
be based upon the Securities Act, the Exchange Act or any other statute or at
common law, on the ground or alleged ground that any Preeffective Prospectus,
the Registration Statement or the Prospectus (or any Preeffective Prospectus,
the Registration Statement or the Prospectus as from time to time amended or
supplemented) includes an untrue statement of a material fact or omits to state
a material fact required to be stated therein or necessary in order to make the
statements therein, in light of the circumstances under which they were made,
not misleading, unless such statement or omission was made in reliance upon, and
in conformity with, written information furnished to the Company by any
Underwriter, directly or through the Representatives, specifically for use in
the preparation thereof; provided, that with respect to any untrue statement or
omission or alleged untrue statement or omission made in any Registration
Statement, the indemnity agreement contained in this subsection (a) shall not
inure to the benefit of any Underwriter Indemnified Party from whom the person
asserting any such losses, claims, damages or liabilities purchased the shares
of Stock concerned to the extent that any such loss, claim, damage or liability
of such Underwriter Indemnified Party results from the fact that a copy of the
Prospectus was not sent or given to such person at or prior to the written
confirmation of the sale of such shares of Stock to such person as required by
the Securities Act and if the untrue statement or omission concerned has been
corrected in the Prospectus. The Company will be entitled to participate at its
own expense in the defense or, if it so elects, to assume the defense of any
suit brought to enforce any such liability, but if the Company elects to assume
the defense, such defense shall be conducted by counsel chosen by it. In the
event the Company elects to assume the defense of any such suit and retain such
counsel, any Underwriter Indemnified Parties, defendant or defendants in the
suit, may retain additional counsel but shall bear the fees and expenses of such
counsel unless (i) the Company shall have specifically authorized in writing the
retaining of such counsel or (ii) the

 
                                      -20-

parties to such suit include any such Underwriter Indemnified Parties, and the
Company and such Underwriter Indemnified Parties at law or in equity have been
advised by counsel to the Underwriters that one or more legal defenses may be
available to it or them which may not be available to the Company, in which case
the Company shall not be entitled to assume the defense of such suit
notwithstanding its obligation to bear the fees and expenses of such counsel.
This indemnity agreement is not exclusive and will be in addition to any
liability which the Company might otherwise have and shall not limit any rights
or remedies which may otherwise be available at law or in equity to each
Underwriter Indemnified Party.

          (b)  Each Selling Stockholder agrees to indemnify and hold harmless
each Underwriter Indemnified Party against any losses, claims, damages,
liabilities or expenses (including, unless such Selling Stockholder elects to
assume the defense, the reasonable cost of investigating and defending against
any claims therefor and counsel fees incurred in connection therewith), joint or
several, which may be based upon the Securities Act, the Exchange Act or any
other statute or at common law, on the ground or alleged ground that any
Preeffective Prospectus, the Registration Statement or the Prospectus (or any
Preeffective Prospectus, the Registration Statement or the Prospectus, as from
time to time amended and supplemented) includes an untrue statement of a
material fact or omits to state a material fact required to be stated therein or
necessary in order to make the statements therein, in light of the circumstances
under which they were made, not misleading, unless such statement or omission
was made in reliance upon, and in conformity with, written information any
Underwriter, directly or through Representatives, specifically for use in the
preparation thereof; provided, that with respect to any untrue statement or
omission or alleged untrue statement or omission made in any Registration
Statement, the indemnity agreement contained in this subsection (b) shall not
inure to the benefit of any Underwriter Indemnified Party from whom the person
asserting any such losses, claims, damages or liabilities purchased the shares
of Stock concerned to the extent that any such loss, claim, damage or liability
of such Underwriter Indemnified Party results from the fact that a copy of the
Prospectus was not sent or given to such person at or prior to the written
confirmation of the sale of such shares of Stock to such person as required by
the Securities Act and if the untrue statement or omission concerned has been
corrected in the Prospectus. Such Selling Stockholder shall be entitled to
participate at his own expense in the defense, or, if he so elects, to assume
the defense of any suit brought to enforce any such liability, but, if such
Selling Stockholder elects to assume the defense, such defense shall be
conducted by counsel chosen by him. In the event that any Selling Stockholder
elects to assume the defense of any such suit and retain such counsel, the
Underwriter Indemnified Parties, defendant or defendants in the suit, may retain
additional counsel but shall bear the fees and expenses of such counsel unless
(i) such Selling Stockholder shall have specifically authorized the retaining of
such counsel or (ii) the parties to such suit include such Underwriter
Indemnified Parties, and such Selling Stockholder and such Underwriter
Indemnified Parties have been advised by counsel that one or more legal defenses
may be available to it or them which may not be available to such Selling
Stockholder, in which case, such Selling Stockholder shall not be entitled to
assume the defense of such suit notwithstanding its obligation to bear the fees
and expenses of such counsel. This indemnity agreement is not exclusive and will
be in addition to any liability which such Selling Stockholder might otherwise
have and shall not limit any rights or remedies which may otherwise be available
at law or in equity to each Underwriter Indemnified Party. The Company and the

 
                                      -21-

Selling Stockholders may agree, as among themselves and without limiting the
rights of the Underwriters under this Agreement, as to their respective amounts
of such liability for which they each shall be responsible.

          (c)  Each Underwriter severally agrees to indemnify and hold harmless
the Company, each of its directors, each of its officers who have signed the
Registration Statement and each person, if any, who controls the Company within
the meaning of the Securities Act (collectively, the "Company Indemnified
Parties") and each Selling Stockholder and each person, if any, who controls a
Selling Stockholder within the meaning of the Securities Act (collectively, the
"Stockholder Indemnified Parties"), against any losses, claims, damages,
liabilities or expenses (including, unless the Underwriter or Underwriters elect
to assume the defense, the reasonable cost of investigating and defending
against any claims therefor and counsel fees incurred in connection therewith),
joint or several, which arise out of or are based in whole or in part upon the
Securities Act, the Exchange Act or any other federal, state, local or foreign
statute or regulation, or at common law, on the ground or alleged ground that
any Preeffective Prospectus, the Registration Statement or the Prospectus (or
any Preeffective Prospectus, the Registration Statement or the Prospectus, as
from time to time amended and supplemented) includes an untrue statement of a
material fact or omits to state a material fact required to be stated therein or
necessary in order to make the statements therein, in light of the circumstances
in which they were made, not misleading, but only insofar as any such statement
or omission was made in reliance upon, and in conformity with, written
information furnished to the Company by such Underwriter, directly or through
the Representatives, specifically for use in the preparation thereof provided,
however, that in no case is such Underwriter to be liable with respect to any
claims made against any Company Indemnified Part or Stockholder with respect to
any claims made against any Company Indemnified Party or Stockholder Indemnified
Part against whom the action is brought unless such Company Indemnified Party or
Stockholder Indemnified Party shall have notified such Underwriter in writing
within a reasonable time after the summons or other first legal process giving
information of the nature of the claim shall have been served upon the Company
Indemnified Party or Stockholder Indemnified Party, but failure to notify such
Underwriter of such claim shall not relieve it from any liability which it may
have to any Company Indemnified Party or Stockholder Indemnified Party otherwise
than on account of its indemnity agreement contained in this paragraph. Such
Underwriter shall be entitled to participate at its own expense in the defense,
or, if it so elects, to assume the defense of any suit brought to enforce any
such liability, but, if such Underwriter elects to assume the defense, such
defense shall be conducted by counsel chosen by it. In the event that any
Underwriter elects to assume the defense of any such suit and retain such
counsel, the Company Indemnified Parties or Stockholder Indemnified Parties and
any other Underwriter or Underwriters or controlling person or persons,
defendant or defendants in the suit, shall bear the fees and expenses of any
additional counsel retained by them, respectively unless (i) the Underwriter
shall have specifically authorized in writing the retaining of such counsel or
(ii) the parties to such suit include the Company or a Stockholder Indemnified
Party, and the Underwriters and such Company or Stockholder Indemnified Party at
law or in equity have been advised by counsel to the Company or such Stockholder
Indemnified Party that one or more defenses may be available to them which may
not be available to the Underwriters, in which case the Underwriters shall not
be entitled to assume the defense of such suit notwithstanding its obligation to
bear fees and expenses of such 

 
                                      -22-

counsel. The Underwriter against whom indemnity may be sought shall not be
liable to indemnify any person for any settlement of any such claim effected
without such Underwriter's consent. This indemnity agreement is not exclusive
and will be in addition to any liability which such Underwriter might otherwise
have and shall not limit any rights or remedies which may otherwise be available
at law or in equity to any Company Indemnified Party or Stockholder Indemnified
Party.

          (d)  If the indemnification provided for in this Section 6 is
unavailable or insufficient to hold harmless an indemnified party under
subsection (a) or (b) or (c) above in respect of any losses, claims, damages,
liabilities or expenses (or actions in respect thereof) referred to herein, then
each indemnifying party shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages, liabilities or
expenses (or actions in respect thereof) in such proportion as is appropriate to
reflect the relative benefits received by the Company and the Selling
Stockholders on the one hand and the Underwriters on the other from the offering
of the Stock. If, however, the allocation provided by the immediately preceding
sentence is not permitted by applicable law, then each indemnifying party shall
contribute to such amount paid or payable by such indemnified party in such
proportion as is appropriate to reflect not only such relative benefits but also
the relative fault of the Company and the Selling Stockholders on the one hand
and the Underwriters on the other in connection with the statements or omissions
which resulted in such losses, claims, damages, liabilities or expenses (or
actions in respect thereof), as well as any other relevant equitable
considerations. The relative benefits received by the Company and the Selling
Stockholders on the one hand and the Underwriters on the other shall be deemed
to be in the same proportion as the total net proceeds from the offering (before
deducting expenses) received by the Company and the Selling Stockholders bear to
the total underwriting discounts and commissions received by the Underwriters,
in each case as set forth in the table on the cover page of the Prospectus. The
relative fault shall be determined by reference to, among other things, whether
the untrue or alleged untrue statement of a material fact or the omission or
alleged omission to state a material fact relates to information supplied by the
Company, the Selling Stockholders or the Underwriters and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission. The Company, the Selling Stockholders and the
Underwriters agree that it would not be just and equitable if contribution were
determined by pro rata allocation (even if the Underwriters were treated as one
entity for such purpose) or by any other method of allocation which does not
take account of the equitable considerations referred to above. The amount paid
or payable by an indemnified party as a result of the losses, claims, damages,
liabilities or expenses (or actions in respect thereof) referred to above shall
be deemed to include any legal or other expenses reasonably incurred by such
indemnified party in connection with investigating, defending, settling or
compromising any such claim. Notwithstanding the provisions of this subsection
(d), no Underwriter shall be required to contribute any amount in excess of the
amount by which the total price at which the shares of the Stock underwritten by
it and distributed to the public were offered to the public exceeds the amount
of any damages which such Underwriter has otherwise been required to pay by
reason of such untrue or alleged untrue statement or omission or alleged
omission. The Underwriters' obligations to contribute are several in proportion
to their respective underwriting obligations and not joint. No person guilty of
fraudulent misrepresentation (within the meaning of Section 

 
                                      -23-

11(f) of the Securities Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation.

          7.   Survival of Indemnities, Representations, Warranties, etc.  The
               ---------------------------------------------------------
respective indemnities, covenants, agreements, representations, warranties and
other statements of the Company, the Selling Stockholders and the several
Underwriters, as set forth in this Agreement or made by them respectively,
pursuant to this Agreement, shall remain in full force and effect, regardless of
any investigation made by or on behalf of any Underwriter, the Selling
Stockholders the Company or any of its officers or directors or any controlling
person, and shall survive delivery of and payment for the Stock.

          8.   Conditions of Underwriters Obligations.  The respective
               --------------------------------------
obligations of the several Underwriters hereunder shall be subject to the
accuracy, at and (except as otherwise stated herein) as of the date hereof and
at and as of the Closing Dates, of the representations and warranties made
herein by the Company and the Selling Stockholders, to compliance at and as of
the Closing Dates by the Company and the Selling Stockholders with their
covenants and agreements herein contained and other provisions hereof to be
satisfied at or prior to the Closing Dates, and to the following additional
conditions:

               (a)  The Registration Statement shall have become effective and
          no stop order suspending the effectiveness thereof shall have been
          issued and no proceedings for that purpose shall have been initiated
          or, to the knowledge of the Company or the Representatives, shall be
          threatened by the Commission, and any request for additional
          information on the part of the Commission (to be included in the
          Registration Statement or the Prospectus or otherwise) shall have been
          complied with to the reasonable satisfaction of the Representatives.
          Any filings of the Prospectus, or any supplement thereto, required
          pursuant to Rule 424 (b) or Rule 434 of the Rules and Regulations,
          shall have been made in the manner and within the time period required
          by Rule 424(b) and Rule 434 of the Rules and Regulations, as the case
          may be.

               (b)  The Representatives shall have been satisfied that there
          shall not have occurred any change prior to the Closing Dates in the
          condition (financial or otherwise), properties, business, management,
          net worth or results of operations of the Company, or any change in
          the capital stock, or any material change in short-term or long-term
          debt of the Company, such that (i) the Registration Statement or the
          Prospectus, or any amendment or supplement thereto, contains an untrue
          statement of fact which, in the opinion of the Representatives, is
          material, or omits to state a fact which, in the opinion of the
          Representatives, is required to be stated therein or is necessary to
          make the statements therein not misleading, or (ii) it is
          unpracticable in the reasonable judgment of the Representatives to
          proceed with the public offering or purchase the Stock as contemplated
          hereby.

               (c)  The Representatives shall be satisfied that no legal or
          governmental action, suit or proceeding affecting the Company which is
          material 

 
                                      -24-

          and adverse to the Company or which affects or may affect the
          Company's or the Selling Stockholders' ability to perform their
          respective obligations under this Agreement shall have been instituted
          or threatened and there shall have occurred no material adverse
          development in any existing such action, suit or proceeding.

               (d)  At the time of execution of this Agreement, the
          Representatives shall have received from Deloitte & Touche LLP,
          independent certified public accountants, a letter, dated the date
          hereof, in form and substance satisfactory to the Underwriters.

               (e)  The Representatives shall have received from Deloitte &
          Touche LLP, independent certified public accountants, a letter, dated
          the Closing Dates, to the effect that such accountants reaffirm, as of
          the Closing Dates, and as though made on the Closing Date(s), the
          statements made in the letter furnished by such accountants pursuant
          to paragraph (d) of this Section 8.

               (f)  The Representatives shall have received from Foley, Hoag &
          Eliot, counsel for the Company and for the Selling of Stockholders, an
          opinion, dated the Closing Dates, to the effect set forth in Exhibit I
          hereto.

               (g)  The Representatives shall have received from Testa, Hurwitz
          & Thibeault, counsel for the Underwriters, their opinion or opinions
          dated the Closing Dates with respect to the incorporation of the
          Company, the validity of the Stock, the Registration Statement and the
          Prospectus and such other related matters as they may reasonably
          request, and the Company and the Selling Stockholders shall have
          furnished to such counsel such documents as they may request for the
          purpose of enabling them to pass upon such matters.

               (h)  The Representatives shall have received a certificate, dated
          the Closing Dates, of the Chief Executive Officer or the President and
          the chief financial or accounting officer of the Company to the effect
          that:

                    (i)    No stop order suspending the effectiveness of the
               Registration Statement has been issued, and, to the best of the
               knowledge of the signers, no proceedings for that purpose have
               been instituted or are pending or contemplated under the
               Securities Act;

                    (ii)   Neither any Preeffective Prospectus, as of its date,
               nor the Registration Statement nor the Prospectus, nor any
               amendment or supplement thereto, as of the time when the
               Registration Statement became effective and at all times
               subsequent thereto up to the delivery of such certificate,
               included any untrue statement of a material fact or omitted to
               state any material fact required to be stated therein or
               necessary to make the statements therein, in light of the
               circumstances under which they were made, not misleading;

 
                                      -25-

                    (iii)  Subsequent to the respective dates as of which
               information is given in the Registration Statement and the
               Prospectus, and except as set forth or contemplated in the
               Prospectus, the Company has not incurred any material liabilities
               or obligations, direct or contingent, nor entered into any
               material transactions not in the ordinary course of business and
               there has not been any material adverse change in the condition
               (financial or otherwise), properties, business, management, net
               worth or results of operations of the Company, or any change in
               the capital stock, or any material change in the short-term or
               long-term debt of the Company;

                    (iv)   The representations and warranties of the Company in
               this Agreement are true and correct at and as of the Closing
               Dates, and the Company has complied with all the agreements and
               performed or satisfied all the conditions on its part to be
               performed or satisfied at or prior to the Closing Dates; and

                    (v)    Since the respective dates as of which information is
               given in the Registration Statement and the Prospectus, and
               except as disclosed in or contemplated by the Prospectus, (i)
               there has not been any material adverse change or a development
               involving a material adverse change in the condition (financial
               or otherwise), properties, business, management, net worth or
               results of operations of the Company; (ii) the business and
               operations conducted by the Company have not sustained a loss by
               strike, fire, flood, accident or other calamity (whether or not
               insured) of such a character as to interfere materially with the
               conduct of the business and operations of the Company; (iii) no
               legal or governmental action, suit or proceeding is pending or
               threatened against the Company which is material to the Company,
               whether or not arising from transactions in the ordinary course
               of business, or which may materially and adversely affect the
               transactions contemplated by this Agreement; (iv) since such
               dates and except as so disclosed, the Company has not incurred
               any material liability or obligation, direct, contingent or
               indirect, made any change in its capital stock (except pursuant
               to its stock plans), made any material change in its short-term
               or funded debt or repurchased or otherwise acquired any of the
               Company's capital stock; and (v) the Company has not declared or
               paid any dividend, or made any other distribution, upon its
               outstanding capital stock payable to stockholders of record on a
               date prior to the Closing Date.

               (i)  The Representatives shall have received a certificate or
          certificates, dated the Closing Dates, of each of the Selling
          Stockholders to the effect that as of the Closing Dates its
          representations and warranties in this Agreement are true and correct
          as if made on and as of the Closing Dates, and that it has performed
          all its obligations and satisfied all the conditions on its part to be
          performed or satisfied at or prior to the Closing Dates.

 
                                      -26-

               (j)  The Company and each of the Selling Stockholders shall have
          furnished to the Representatives such additional certificates as the
          Representatives may have reasonably requested as to the accuracy, at
          and as of the Closing Dates, of the representations and warranties
          made herein by them and as to compliance at and as of the Closing
          Dates by them with their covenants and agreements herein contained and
          other provisions hereof to be satisfied at or prior to the Closing
          Dates, and as to satisfaction of the other conditions to the
          obligations of the Underwriters hereunder.

               (k)  Cowen shall have received the written agreements of the
          officers, directors and holders of Common Stock and options to
          purchase Common Stock listed in Schedule C that each will not offer,
          sell, assign, transfer, encumber, contract to sell, grant an option to
          purchase or otherwise dispose of, other than by operation of law,
          gifts, pledges or dispositions by estate representatives, any shares
          of Common Stock (including, without limitation, Common Stock of the
          Company which may be deemed to be beneficially owned by the
          undersigned in accordance with the Rules and Regulations) during the
          180 days following the date of the final Prospectus, except for the
          Stock being sold hereunder by the Selling Stockholders.

          All opinions, certificates, letters and other documents will be in
compliance with the provisions hereunder only if they are satisfactory in form
and substance to the Representatives. The Company will furnish to the
Representatives conformed copies of such opinions, certificates, letters and
other documents as the Representatives shall reasonably request. If any of the
conditions hereinabove provided for in this Section shall not have been
satisfied when and as required by this Agreement, this Agreement may be
terminated by the Representatives by notifying the Company of such termination
in writing or by telegram at or prior to the Closing Dates, but Cowen shall be
entitled to waive any of such conditions.

          9.   Effective Date.  This Agreement shall become effective
               --------------
immediately as to Sections 5, 6, 7, 9, 10, 11, 13, 14, 15, 16 and 17 and, as to
all other provisions, at 11:00 a.m. New York City time on the first full
business day following the effectiveness of the Registration Statement or at
such earlier time after the Registration Statement becomes effective as the
Representatives may determine on and by notice to the Company or by release of
any of the Stock for sale to the public. For the purposes of this Section 9, the
Stock shall be deemed to have been so released upon the release for publication
of any newspaper advertisement relating to the Stock or upon the release by you
of telegrams (i) advising Underwriters that the shares of Stock are released for
public offering or (ii) offering the Stock for sale to securities dealers,
whichever may occur first.

          10.  Termination.  This Agreement (except for the provisions of
               -----------  
Section 5) may be terminated by the Company at any time before it becomes
effective in accordance with Section 9 by notice to the Representatives and may
be terminated by the Representatives at any time before it becomes effective in
accordance with Section 9 by notice to the Company. In the

 
                                      -27-

event of any termination of this Agreement under this or any other provision of
this Agreement, there shall be no liability of any party to this Agreement to
any other party, other than as provided in Sections 5, 6 and 11 and other than
as provided in Section 12 as to the liability of defaulting Underwriters.

          This Agreement may be terminated after it becomes effective by the
Representatives by notice to the Company (i) if at or prior to the First Closing
Date, or the Option Closing Date trading in securities on any of the New York
Stock Exchange, American Stock Exchange, or the Nasdaq National Market shall
have been suspended or minimum or maximum prices shall have been established on
any such exchange or market, or a banking moratorium shall have been declared by
New York or United States authorities; (ii) trading of any securities of the
Company shall have been suspended on any exchange or in any over-the-counter
market; (iii) if at or prior to the First Closing Date or the Option Closing
Date there shall have been (A) an outbreak or escalation of hostilities between
the United States and any foreign power or of any other insurrection or armed
conflict involving the United States or (B) any change in financial markets or
any calamity or crisis which, in the judgment of the Representatives, makes it
impractical or inadvisable to offer or sell the Firm Stock or Optional Stock, as
applicable, on the terms contemplated by the Prospectus; (iv) if there shall
have been any development or prospective development involving particularly the
business or properties or securities of the Company or the transactions
contemplated by this Agreement, which, in the judgment of the Representatives,
makes it impracticable or inadvisable to offer or deliver the Firm Stock or the
Optional Stock, as applicable, on the terms contemplated by the Prospectus; (v)
if there shall be any litigation or proceeding, pending or threatened, which, in
the judgment of the Representatives, makes it impracticable or inadvisable to
offer or deliver the Firm Stock or Optional Stock, as applicable, on the terms
contemplated by the Prospectus; or (vi) if there shall have occurred any of the
events specified in the immediately preceding clauses (i) - (v) together with
any other such event that makes it, in the judgment of the Representatives,
impractical or inadvisable to offer or deliver the Firm Stock or Optional Stock,
as applicable, on the terms contemplated by the Prospectus.

          11.  Reimbursement of Underwriters.  Notwithstanding any other
               -----------------------------
provisions hereof, if this Agreement shall not become effective by reason of any
election of the Company or the Selling Stockholders pursuant to the first
paragraph of Section 10 or shall be terminated by the Representatives under
Section 8 or Section 10, the Company will bear and pay the expenses specified in
Section 5 hereof and, in addition to their obligations pursuant to Section 6
hereof, the Company will reimburse the reasonable out-of-pocket expenses of the
several Underwriters (including reasonable fees and disbursements of counsel for
the Underwriters) incurred in connection with this Agreement and the proposed
purchase of the Stock, and promptly upon demand the Company will pay such
amounts to you as Representatives.

          12.  Substitution of Underwriters.  If any Underwriter or Underwriters
               ----------------------------
shall default in its or their obligations to purchase shares of Stock hereunder
and the aggregate number of shares which such defaulting Underwriter or
Underwriters agreed but failed to purchase does not exceed ten percent (10%) of
the total number of shares underwritten, the other Underwriters shall be
obligated severally, in proportion to their respective commitments hereunder, to

 
                                      -28-

purchase the shares which such defaulting Underwriter or Underwriters agreed but
failed to purchase. If any Underwriter or Underwriters shall so default and the
aggregate number of shares with respect to which such default or defaults occur
is more than ten percent (10%) of the total number of shares underwritten and
arrangements satisfactory to the Representatives and the Company for the
purchase of such shares by other persons are not made within forty-eight (48)
hours after such default, this Agreement shall terminate.

          If the remaining Underwriters or substituted Underwriters are required
hereby or agree to take up all or part of the shares of Stock of a defaulting
Underwriter or Underwriters as provided in this Section 12, (i) the Company and
the Selling Stockholders shall have the right to postpone the Closing Dates for
a period of not more than five (5) full business days in order that the Company
and the Selling Stockholders may effect whatever changes may thereby be made
necessary in the Registration Statement or the Prospectus, or in any other
documents or arrangements, and the Company agrees promptly to file any
amendments to the Registration Statement or supplements to the Prospectus which
may thereby be made necessary, and (ii) the respective numbers of shares to be
purchased by the remaining Underwriters or substituted Underwriters shall be
taken as the basis of their underwriting obligation for all purposes of this
Agreement. Nothing herein contained shall relieve any defaulting Underwriter of
its liability to the Company, the Selling Stockholders or the other Underwriters
for damages occasioned by its default hereunder. Any termination of this
Agreement pursuant to this Section 12 shall be without liability on the part of
any non-defaulting Underwriter, the Selling Stockholders or the Company, except
for expenses to be paid or reimbursed pursuant to Section 5 and except for the
provisions of Section 6.

          13.  Notices.  All communications hereunder shall be in writing and,
               -------
if sent to the Underwriters shall be mailed, delivered or telegraphed and
confirmed to you, as their Representatives c/o Cowen & Company at Financial
Square, New York, New York 10005 except that notices given to an Underwriter
pursuant to Section 6 hereof shall be sent to such Underwriter at the address
furnished by the Representatives or, if sent to the Company, shall be mailed,
delivered or telegraphed and confirmed at Lightbridge, Inc., 281 Winter Street,
Waltham, Massachusetts 02154. With respect to the Selling Stockholders, notices
may be sent to an Attorney-in-Fact.

          14.  Successors.  This Agreement shall inure to the benefit of and be
               ----------
binding upon the several Underwriters, the Company and the Selling Stockholders
and their respective successors and legal representatives. Nothing expressed or
mentioned in this Agreement is intended or shall be construed to give any person
other than the persons mentioned in the preceding sentence any legal or
equitable right, remedy or claim under or in respect of this Agreement, or any
provisions herein contained, this Agreement and all conditions and provisions
hereof being intended to be and being for the sole and exclusive benefit of such
persons and for the benefit of no other person; except that the representations,
warranties, covenants, agreements and indemnities of the Company and the Selling
Stockholders contained in this Agreement shall also be for the benefit of 

 
                                      -29-

the person or persons, if any, who control any Underwriter or Underwriters
within the meaning of Section 15 of the Securities Act or Section 20 of the
Exchange Act, and the indemnities of the several Underwriters shall also be for
the benefit of each director of the Company, each of its officers who has signed
the Registration Statement and the person or persons, if any, who control the
Company or any Selling Stockholders within the meaning of Section 15 of the
Securities Act or Section 20 of the Exchange Act.

          15.  Applicable Law.  This Agreement shall be governed by and
               --------------
construed in accordance with the laws of the State of New York.

          16.  Authority of the Representatives.  In connection with this
               --------------------------------
Agreement, you will act for and on behalf of the several Underwriters, and any
action taken under this Agreement by Cowen, as Representative, will be binding
on all the Underwriters; and any action taken under this Agreement by any of the
Attorneys-in-fact will be binding on all of the Selling Stockholders.

          17.  Partial Unenforceability.  The invalidity or unenforceability of
               ------------------------
any Section, paragraph or provision of this Agreement shall not affect the
validity or enforceability of any other Section, paragraph or provision hereof.
If any Section, paragraph or provision of this Agreement is for any reason
determined to be invalid or unenforceable, there shall be deemed to be made such
minor changes (and only such minor changes) as are necessary to make it valid
and enforceable.

          18.  General.  This Agreement constitutes the entire agreement of the
               -------
parties to this Agreement and supersedes all prior written or oral and all
contemporaneous oral agreements, understandings and negotiations with respect to
the subject matter hereof.

          In this Agreement, the masculine, feminine and neuter genders and the
singular and the plural include one another. The section headings in this
Agreement are for the convenience of the parties only and will not affect the
construction or interpretation of this Agreement. This Agreement may be amended
or modified, and the observance of any term of this Agreement may be waived,
only by a writing signed by the Company, the Selling Stockholders and the
Representatives.

          19.  Counterparts.  This Agreement may be signed in two (2) or more
               ------------
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto and hereto were upon the same instrument.

          Any person executing and delivering this Agreement as Attorney-in-fact
for the Selling Stockholders represents by so doing that he has been duly
appointed as Attorney-in-fact by such Selling Stockholder pursuant to a validly
existing and binding Power of Attorney which authorizes such Attorney-in-fact to
take such action.

 
                                      -30-

          If the foregoing correctly sets forth our understanding, please
indicate your acceptance thereof in the space provided below for that purpose,
whereupon this letter and your acceptance shall constitute a binding agreement
between us.

                                        Very truly yours,
                                        LIGHTBRIDGE, INC.


                                        
                                        By:____________________________________
                                                 Name:
                                                 Title:


                                        SELLING STOCKHOLDERS LISTED
                                        IN SCHEDULE B


                                        By:_____________________________________
                                                 less than more than
                                                 Attorney-in-fact

                                        By:_____________________________________
                                                 less than more than
                                                 Attorney-in-fact

                                        Acting on behalf of the Selling 
                                        Stockholders listed in Schedule B.

 
                                      -31-


Accepted and delivered in
New York New York as of
the date first above written.

COWEN & COMPANY
MONTGOMERY SECURITIES
PRUDENTIAL SECURITIES   
    INCORPORATED

By:  COWEN & COMPANY
Acting on their own behalf and as 
Representatives of several Underwriters
referred to in the foregoing Agreement.

By:  Cowen Incorporated,
     its general partner


By:_____________________________
   Name:
   Title:

 
                                     -32-

                                  SCHEDULE A


 
 
                                                                   Number  
                                                                   of Firm 
                                                                   Shares  
                                                                    to be  
Name                                                              Purchased
- ----                                                              --------- 
                                                                
Cowen & Company.............................................
Montgomery Securities.......................................
Prudential Securities Incorporated..........................












    Total...................................................
                                                                  =========
 

 
                                      -33-

                                  SCHEDULE B


                                                   Number       Number       
                                                     of           of           
                                                  Optional       Firm         
                                                  Shares to    Shares to    
                                                   be Sold      be Sold       
                                                   -------      -------

Selling Stockholders
- --------------------

 
                                     -34-

                                  SCHEDULE C

                               LOCKUP AGREEMENTS



[to include all stock and optionholders]