CYTOGEN CORPORATION

                        2005 EMPLOYEE STOCK PURCHASE PLAN








1.   PURPOSE OF THE PLAN

     The Cytogen  Corporation  2005 Employee  Stock Purchase Plan is intended to
promote the  interests  of the  Company  (as defined in Article 2) by  providing
eligible  employees of a  Participating  Employer (as defined in Article 2) with
the  opportunity  to  acquire a  proprietary  interest  in the  Company  through
participation in a payroll deduction-based employee stock purchase plan designed
to qualify under  section 423 of the Internal  Revenue Code of 1986, as amended.
The Plan is not intended and shall not be construed as constituting an "employee
benefit  plan,"  within the meaning of section 3(3) of the  Employee  Retirement
Income Security Act of 1974, as amended.

     The Board (as defined in Article 2) has adopted the Plan to be effective as
of October 1, 2005,  subject to  shareholder  approval of the Plan.  The Company
expects to submit the Plan to the  shareholders  of the Company for  approval at
the Company's 2006 annual meeting in June,  2006. The first Purchase  Period (as
defined in Article  2) under the Plan ends on June 30,  2006.  If for any reason
the  shareholders  of the  Company do not approve the Plan on or before June 30,
2006,  the first  Purchase  Period shall  terminate  on a date  specified by the
Board, the Plan shall  immediately  terminate,  and no purchases of Common Stock
(as defined in Article 2) shall be made under the Plan.

2.   DEFINITIONS

       (a) "Board" shall mean the Company's Board of Directors.

       (b) "Code" shall mean the Internal Revenue Code of 1986, as amended.

       (c) "Change of Control" shall be deemed to have occurred if:

               (i)   Any "person" (as such  term is used in  sections  13(d) and
          14(d) of the Exchange Act) becomes a "beneficial owner" (as defined in
          Rule  13d-3  under the  Exchange  Act),  directly  or  indirectly,  of
          securities  of the  Company  representing  more than 50% of the voting
          power of the then outstanding securities of the Company; provided that
          a Change  of  Control  shall  not be  deemed to occur as a result of a
          transaction  in which the  Company  becomes a  subsidiary  of  another
          corporation and in which the shareholders of the Company,  immediately
          prior to the transaction, will beneficially own, immediately after the
          transaction,  shares  entitling such  shareholders to more than 50% of
          all votes to which all shareholders of the parent corporation would be
          entitled in the election of directors; or

               (ii)  The consummation  of (i) a merger or  consolidation  of the
          Company  with  another  corporation  where  the  shareholders  of  the
          Company,  immediately prior to the merger or  consolidation,  will not
          beneficially  own,  immediately  after the  merger  or  consolidation,
          shares  entitling such  shareholders  to more than 50% of all votes to
          which all shareholders of the surviving  corporation would be entitled
          in the election of directors,  (ii) a sale or other

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          disposition of all or substantially  all of the assets of the Company,
          or (iii) a liquidation or dissolution of the Company.

       (d) "Common Stock" shall mean the common stock of the Company.

       (e) "Company  Affiliate" shall  mean any parent or subsidiary corporation
of the Company (as determined in accordance with Code section 424),  whether now
existing or subsequently established.

       (f) "Company" shall mean Cytogen Corporation, a Delaware corporation, and
any  corporate  successor  to all or  substantially  all of the assets or voting
stock of Cytogen Corporation that shall adopt the Plan.

       (g) "Compensation"  shall  mean (i)  the regular  base  salary paid  to a
Participant  by one or more  Participating  Employers  during the  Participant's
period  of  participation  in a  Purchase  Period  under  the Plan plus (ii) all
overtime payments, bonuses and commissions received during such Purchase Period.
Such  Compensation  shall be  calculated  before  deduction of (A) any income or
employment tax withholdings or (B) any contributions  made by the Participant to
any Code section  401(k) salary  deferral  plan,  any Code section 125 cafeteria
benefit  program or any Code section  132(f)(4)  transportation  fringe  benefit
program now or hereafter  established  by the Company or any Company  Affiliate.
However, Compensation shall not include any contributions made by the Company or
any Company  Affiliate on the  Participant's  behalf to any employee  benefit or
welfare plan now or hereafter  established (other than Code section 401(k), Code
section  125,  or  Code  section  132(f)(4)  contributions  deducted  from  such
Compensation).

       (h) "Effective Date" shall mean October 1, 2005.

       (i) "Eligible  Employee"  shall  mean  any person  who is  employed  by a
Participating  Employer as an  employee  on a basis under which he is  regularly
expected  to render  more than 20 hours of  service  per week for more than five
months per  calendar  year,  for  earnings  considered  wages under Code section
3401(a). However, an "Eligible Employee" shall not include any person who would,
immediately after the grant of a purchase right under this Plan, own (within the
meaning of Code section 424(d)) or hold  outstanding  options or other rights to
purchase stock possessing 5% or more of the total combined voting power or value
of all classes of stock of the Company or any Company Affiliate.

       (j) "Entry Date" means the first day of a Purchase Period.

       (k) "Exchange  Act" shall  mean the Securities  Exchange Act  of 1934, as
amended.

       (l) "Fair  Market Value"  per share of  Common Stock on any relevant date
shall be determined in accordance with the following provisions:

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               (i)  If  the  Common Stock  is at the time  traded on the  Nasdaq
          National  Market,  then the Fair  Market  Value  shall be the  closing
          selling  price per share of Common Stock on the date in  question,  as
          such price is  reported  by the  National  Association  of  Securities
          Dealers on the Nasdaq National Market and published in The Wall Street
          Journal.  If there is no closing selling price for the Common Stock on
          the date in question,  then the Fair Market Value shall be the closing
          selling  price on the last  preceding  date for which  such  quotation
          exists.

               (ii)  If the Common Stock is at the time  listed on the New  York
          Stock Exchange or American Stock Exchange,  then the Fair Market Value
          shall be the closing  selling  price per share of Common  Stock on the
          date  in  question  on the  stock  exchange  determined  by  the  Plan
          Administrator  to be the primary market for the Common Stock,  as such
          price is officially  quoted in the composite tape of  transactions  on
          such exchange and published in The Wall Street Journal. If there is no
          closing  selling  price for the Common  Stock on the date in question,
          then the Fair Market Value shall be the closing  selling  price on the
          last preceding date for which such quotation exists.

       (m) "Participant"  shall mean  any Eligible  Employee of a  Participating
Employer who is actively participating in the Plan.

       (n) "Participating  Employer"  shall mean  the Company  and such  Company
Affiliates  as may be  authorized  from time to time by the Board to extend  the
benefits of the Plan to their Eligible Employees.

       (o) "Plan"  shall  mean  the  Cytogen  Corporation  2005  Employee  Stock
Purchase Plan, as set forth in this document, and as amended from time to time.

       (p) "Plan Administrator" shall  mean the committee appointed by the Board
to administer the Plan.

       (q) "Purchase  Date" shall  mean the  last business day of  each Purchase
Period. The initial Purchase Date shall be June 30, 2006.

       (r) "Purchase Period" shall mean the period beginning October 1, 2005 and
ending June 30, 2006, and each  successive  three-month  period (or other period
designated  by the Plan  Administrator),  at the end of which  shares  of Common
Stock shall be purchased on behalf of each Participant.  Beginning July 1, 2006,
Purchase Periods shall begin on July 1, October 1, January 1 and April 1, unless
the Plan Administrator determines otherwise.

       (s) "Term of Service" means  a consecutive one-month  period during which
an individual was an employee of the Company or a Company Affiliate.

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3.   PURCHASE PERIODS

       (a) Purchase  Periods.  Shares of  Common  Stock  shall  be  offered  for
purchase under the Plan through a series of consecutive  Purchase  Periods until
such time as (i) the  maximum  number of shares of Common  Stock  available  for
issuance  under the Plan shall have been  purchased  or (ii) the Plan shall have
been sooner terminated.

       (b) Duration of Purchase Periods. Each  Purchase Period shall  be of such
duration  (not  to  exceed  24  months)  as  shall  be  determined  by the  Plan
Administrator  prior to the beginning of the Purchase Period. The first Purchase
Period  shall  begin on October 1, 2005 and shall end on June 30,  2006.  On and
after July 1,  2006,  each  Purchase  Period  shall  commence  at a  three-month
interval  on  each  July  1,  October  1,  January  1  and  April  1.  The  Plan
Administrator  may establish  different  (shorter or longer)  Purchase  Periods,
before  the  beginning  of  the  applicable   Purchase   Period,   as  the  Plan
Administrator deems appropriate.

4.   ELIGIBILITY

       (a) Commencement of Participation.  Except  as provided  in Article 7, an
Eligible  Employee who has  completed a Term of Service  prior to the  Effective
Date and who is employed by a Participating Employer on the Effective Date shall
be eligible  to  participate  in the Plan as of the  Effective  Date.  All other
Eligible  Employees,  except as  provided  in Article 7,  shall be  eligible  to
participate in the Plan as of the Entry Date  coinciding  with or next following
the completion of a Term of Service.

       (b) Enrollment  Forms.  In  order  to  participate  in  the  Plan  for  a
particular  Purchase  Period,  an Eligible  Employee must complete an enrollment
form prescribed by the Plan Administrator  (including a stock purchase agreement
and a  payroll  deduction  authorization)  and  file  such  forms  with the Plan
Administrator  (or its  designee)  at such time  before  the Entry Date for that
Purchase Period as may be determined by the Plan Administrator.

5.   PAYROLL DEDUCTIONS

       (a) Elections.  The payroll  deduction  authorized  by  a Participant for
purposes of acquiring shares of Common Stock during a Purchase Period may be any
multiple of 1% of the Compensation  paid to the Participant  during the Purchase
Period, up to a maximum of 10% of Compensation. The deduction rate so authorized
shall continue in effect  throughout the Purchase  Period,  except to the extent
such rate is changed in accordance with the following guidelines:

               (i)  The Participant may, at any time during the Purchase Period,
          reduce his rate of payroll  deduction,  to become effective as soon as
          possible   after   filing   the   appropriate   form   with  the  Plan
          Administrator.  The  Participant  may not  effect  more  than one such
          reduction per Purchase Period.

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               (ii) Prior  to  the  commencement of a ny new Purchase  Period, a
          Participant  may increase the rate of his payroll  deduction by filing
          the appropriate form with the Plan Administrator.  The new rate (which
          may not exceed 10% of Compensation) shall become effective on the next
          Entry Date following the filing of such form.

       (b) Commencement. Payroll  deductions shall begin on the first pay day as
of which  commencement is  administratively  feasible following the beginning of
the Purchase  Period and shall (unless  sooner  terminated  by the  Participant)
continue through the pay day ending with or immediately prior to the last day of
the  Purchase  Period.  The  amounts so  collected  shall be  credited to a book
account  established  on the  Company's  records  for  the  Participant,  but no
interest  shall be paid on the  balance  from time to time  outstanding  in such
account.  The amounts collected from the Participant shall not be required to be
held in any  segregated  account  or trust fund and may be  commingled  with the
general assets of the Company and used for general corporate purposes.

       (c) Cessation   of   Payroll   Deductions.  Payroll   deductions    shall
automatically cease upon the termination of the Participant's  purchase right in
accordance with the Plan.

6.   PURCHASE RIGHTS

       (a) Grant  of Purchase  Rights. A Participant shall be granted a separate
purchase right for each Purchase Period in which he enrolls.  The purchase right
shall be granted on the Entry Date of the Purchase  Period and shall provide the
Participant  with the right to purchase  shares of Common  Stock,  at the end of
that Purchase  Period,  upon the terms set forth below.  The  Participant  shall
execute  a  stock  purchase  agreement  embodying  such  terms  and  such  other
provisions (not inconsistent  with the Plan) as the Plan  Administrator may deem
advisable.

       (b) Exercise  of  the  Purchase  Right.  Each  purchase  right  shall  be
automatically exercised on the Purchase Date for the Purchase Period, and shares
of Common Stock shall  accordingly be purchased on behalf of each Participant on
the Purchase Date. The purchase shall be effected by applying the  Participant's
payroll  deductions  for the Purchase  Period to the purchase of whole shares of
Common  Stock at the  purchase  price in  effect  for the  Participant  for that
Purchase Date.

       (c) Purchase  Price. Unless the Plan  Administrator determines  otherwise
prior to the beginning of the Purchase  Period,  the purchase price per share at
which Common Stock will be purchased on the Participant's behalf on the Purchase
Date shall be equal to the lower of (i) 85% of the Fair  Market  Value per share
of Common Stock on the Entry Date of the Purchase Period or (ii) 85% of the Fair
Market Value per share of Common Stock on the Purchase Date.

       (d) Number  of Purchasable  Shares. The number of shares  of Common Stock
purchasable by a Participant on the Purchase Date for a Purchase Period shall be
the number of whole shares  obtained by dividing the amount  collected  from the
Participant through

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payroll  deductions  during the Purchase  Period by the purchase price in effect
for the  Participant  for that Purchase  Date.  However,  the maximum  number of
shares of Common Stock that may be purchased  by a  Participant  on any Purchase
Date shall not exceed the largest number of whole shares of Common Stock as does
not exceed  the number of shares  determined  by  dividing  $18,750 in the first
nine-month  Purchase Period (and $6,250 during any three-month  Purchase Period)
by the purchase price as of the Entry Date for the Purchase  Period,  determined
as described in subsection (c)(i) above. The Plan  Administrator  shall have the
discretionary authority,  exercisable prior to the start of any Purchase Period,
to increase or decrease the limitations to be in effect for the number of shares
purchasable per Participant for the Purchase Period.

       (e) Excess  Payroll  Deductions.  Any payroll  deductions  that  are  not
applied to the purchase of shares of Common  Stock on any Purchase  Date because
they are not  sufficient to purchase a whole share of Common Stock shall be held
for the  purchase  of  Common  Stock  on the  next  Purchase  Date,  unless  the
Participant  requests a refund.  Any payroll  deductions that are not applied to
the purchase of Common Stock by reason of the  limitation on the maximum  number
of shares  purchasable  per  Participant as of a Purchase Date shall be promptly
refunded.

       (f) Suspension of Payroll Deductions. In the event that a Participant is,
by reason of the accrual  limitations in Article 7,  precluded  from  purchasing
additional  shares of Common Stock on a Purchase Date,  then no further  payroll
deductions  shall be  collected  from  such  Participant  with  respect  to that
Purchase Period.

       (g) Withdrawal  from  Purchase  Period. The  following  provisions  shall
govern a Participant's withdrawal from a Purchase Period:

               (i)   A Participant  may  withdraw  from the  Purchase  Period in
          which he is enrolled at any time prior to the Purchase  Date by filing
          the appropriate  form with the Plan  Administrator  (or its designee),
          and  no  further  payroll  deductions  shall  be  collected  from  the
          Participant  with  respect  to  that  Purchase  Period.   Any  payroll
          deductions   collected  during  the  Purchase  Period  in  which  such
          withdrawal occurs shall, at the Participant's election, be immediately
          refunded or held for the purchase of shares on the Purchase  Date.  If
          no such  election  is made at the  time of such  withdrawal,  then the
          payroll deductions  collected from the Participant during the Purchase
          Period in which such  withdrawal  occurs  shall be refunded as soon as
          possible.

               (ii) The Participant's withdrawal from a Purchase Period shall be
          irrevocable,  and the  Participant  may not  subsequently  rejoin that
          Purchase Period at a later date. In order to resume  participation  in
          any subsequent  Purchase Period, the Participant must re-enroll in the
          Plan (by making a timely filing of the prescribed enrollment forms) on
          or before the Entry Date of the subsequent Purchase Period.

                                       6



       (h) Termination  of  Purchase  Right. If  a  Participant  ceases to be an
Eligible  Employee  for any reason  (including  death,  disability  or change in
status) while his purchase right remains outstanding, the Participant's purchase
right  shall  immediately  terminate,  and  all  of  the  Participant's  payroll
deductions  for the Purchase  Period in which the purchase  right so  terminates
shall be immediately refunded to the Participant.

       (i) Change  of  Control.   Unless  the   Plan  Administrator   determines
otherwise,  immediately  prior to the effective date of any Change of Control of
the Company, each outstanding purchase right shall automatically be exercised by
applying the payroll  deductions of each  Participant for the Purchase Period in
which the Change of Control  occurs to the  purchase  of whole  shares of Common
Stock at a  purchase  price per share  equal to the lower of (i) 85% of the Fair
Market Value per share of Common  Stock on the first day of the Purchase  Period
or (ii) 85% of the Fair Market Value per share of Common Stock immediately prior
to the effective  date of the Change of Control,  or such other  purchase  price
formula as may be in effect for the Purchase  Period  consistent  with the Plan.
The  applicable  limitation on the number of shares of Common Stock  purchasable
per Participant shall continue to apply to any such purchase.

       (j) Proration of Purchase Rights. If the total number of shares of Common
Stock to be purchased pursuant to outstanding  purchase rights on any particular
date exceeds the number of shares then  available  for issuance  under the Plan,
the Plan Administrator  shall make a pro-rata allocation of the available shares
on a uniform and  nondiscriminatory  basis,  and the payroll  deductions of each
Participant, to the extent in excess of the aggregate purchase price payable for
the Common Stock pro-rated to such Participant, shall be refunded.

       (k) Assignability.  A purchase  right shall  be exercisable  only by  the
Participant and shall not be assignable or transferable by the Participant.

       (l) Stockholder  Rights. A Participant  shall have no  stockholder rights
with respect to the shares subject to his  outstanding  purchase right until the
shares  are  purchased  on the  Participant's  behalf  in  accordance  with  the
provisions of the Plan and the  Participant has become a holder of record of the
purchased shares.

7.   ACCRUAL LIMITATIONS

       (a) Dollar  Limitation. No Participant shall be entitled to accrue rights
to acquire Common Stock pursuant to any purchase  right  outstanding  under this
Plan if and to the extent that such accrual,  when aggregated with (i) rights to
purchase  Common Stock accrued under any other purchase right granted under this
Plan and (ii) similar  rights  accrued under other employee stock purchase plans
(within  the  meaning  of  Code  section  423)  of the  Company  or any  Company
Affiliate,  would otherwise permit the Participant to purchase more than $25,000
worth of stock of the Company or any Company Affiliate  (determined on the basis
of the Fair Market Value per share on the date or dates such rights are granted)
for each  calendar  year in which such rights are at any time  outstanding.  For
purposes of applying such accrual  limitations  to the purchase  rights  granted
under the Plan, the following provisions shall apply:

                                       7



               (i)   The  right to acquire  Common Stock under  each outstanding
          purchase  right shall accrue on each Purchase Date on which such right
          is outstanding.

               (ii)  No  right  to acquire  Common Stock  under any  outstanding
          purchase right shall accrue to the extent the  Participant has already
          accrued in the same  calendar  year the right to acquire  Common Stock
          under one or more  other  purchase  rights at a rate  equal to $25,000
          worth of Common  Stock  (determined  on the  basis of the Fair  Market
          Value per share on the date or dates of grant) for each  calendar year
          in which such rights were at any time outstanding.

       (b) Refund.  If by reason of such accrual limitations, any purchase right
of a  Participant  does not accrue for a particular  Purchase  Period,  then the
payroll  deductions that the  Participant  made during that Purchase Period with
respect to such purchase right shall be promptly refunded.

8.   RESTRICTION ON SHARE TRANSFERS FOR OFFICERS

     Participants who are officers of the Company or a Company Affiliate may not
transfer  shares of  Common  Stock  purchased  under the Plan for a period of 12
months after the Purchase Date as of which the shares are  purchased;  provided,
however,  that this restriction shall cease to apply upon a Change of Control of
the Company or under such other circumstances as the Board deems appropriate.

9.   ADMINISTRATION OF THE PLAN

     The Plan Administrator shall have full discretionary authority to interpret
and construe any  provision of the Plan and to adopt such rules and  regulations
for  administering the Plan as it may deem necessary in order to comply with the
requirements of Code section 423. Decisions of the Plan  Administrator  shall be
final and binding on all parties  having an interest in the Plan. As a condition
of participating in the Plan, all Participants must  acknowledge,  in writing or
by  completing  the  enrollment  forms  to  participate  in the  Plan,  that all
decisions  and  determinations  of the Plan  Administrator  shall  be final  and
binding on the  Participant,  his  beneficiaries  and any other person having or
claiming an interest under the Plan on behalf of the Participant.

10.  STOCK SUBJECT TO PLAN

       (a) Number  of  Shares. Subject  to a djustment as  described below,  the
aggregate  number of shares of Common Stock of the Company that may be issued or
transferred  under the Plan is 500,000 shares.  The stock  purchasable under the
Plan shall be shares of  authorized  but unissued or  reacquired  Common  Stock,
including shares of Common Stock purchased on the open market.

       (b) Adjustment. If  any change is  made to the Common  Stock by reason of
any stock  split,  stock  dividend,  recapitalization,  combination  of  shares,
exchange of shares or

                                       8



other change  affecting  the  outstanding  Common  Stock as a class  without the
Company's receipt of consideration,  the Plan Administrator may make appropriate
adjustments to (i) the maximum number and class of securities issuable under the
Plan,  (ii)  the  maximum  number  and  class  of  securities   purchasable  per
Participant  on any Purchase  Date, and (iii) the number and class of securities
and the price per share in effect  under each  outstanding  purchase  right,  in
order to prevent the dilution or enlargement of benefits thereunder.

11.  EFFECTIVE DATE AND TERM OF THE PLAN

       (a) Effective  Date. The Plan  was adopted by the  Board on September 23,
2005,  and shall  become  effective  at the  Effective  Date,  provided  that no
purchase  rights  granted  under the Plan shall be  exercised,  and no shares of
Common  Stock shall be purchased  hereunder,  until (i) the Plan shall have been
approved by the  stockholders  of the  Company  and (ii) the Company  shall have
complied with all  applicable  requirements  of the  Securities  Act of 1933, as
amended (including the registration of the shares of Common Stock issuable under
the Plan on a Form S-8  registration  statement  filed with the  Securities  and
Exchange  Commission),  and all applicable  listing  requirements  of the Nasdaq
National Market (or other stock exchange if applicable) and all other applicable
requirements  established by law or regulation  have been met. In the event such
stockholder approval is not obtained, or such compliance is not effected, within
12 months  after  the date on which the Plan is  adopted  by the Board  (or,  if
earlier,  by June 30, 2006),  the Plan shall terminate and have no further force
or effect, and all sums collected from Participants  during the initial Purchase
Period hereunder shall be refunded.

       (b) Term. Unless sooner terminated by the Board, the Plan shall terminate
upon the  earliest  of (i)  September  22,  2015,  (ii) the  date on  which  all
shares  available  for issuance  under the Plan shall have been sold pursuant to
purchase rights exercised under the Plan or (iii) the date on which all purchase
rights are exercised in connection with a change of control. No further purchase
rights shall be granted or exercised, and no further payroll deductions shall be
collected, under the Plan following such termination.

12.  AMENDMENT AND TERMINATION

       (a) Amendment;  Termination.  The Board  may  alter,  amend,  suspend  or
terminate  the  Plan  at any  time.  In  the  event  of  Plan  termination,  any
outstanding  payroll  deductions that are not used to purchase Common Stock on a
Purchase  Date  pursuant to the Plan shall be refunded to such  Participants  as
soon as administratively possible.

       (b) Stockholder  Approval. In  no event  may the Board  effect any of the
following  amendments  or  revisions  to the Plan  without  the  approval of the
Company's  stockholders:  (i)  increase  the  number of  shares of Common  Stock
issuable  under the Plan,  except for  permissible  adjustments  in the event of
certain changes in the Company's  capitalization,  (ii) alter the purchase price
formula  so as to reduce the  purchase  price  payable  for the shares of Common
Stock  purchasable  under the Plan or (iii) modify the eligibility  requirements
for participation in the Plan.

                                       9



13.  GENERAL PROVISIONS

       (a) Expenses.  All costs and expenses  incurred in the administration  of
the Plan shall be paid by the Company; however, each Plan Participant shall bear
all  costs  and  expenses  incurred  by such  individual  in the  sale or  other
disposition of any shares purchased under the Plan.

       (b) No  Right of  Employment. Nothing  in the Plan shall  confer upon the
Participant  any right to  continue  in the employ of the Company or any Company
Affiliate or interfere  with or otherwise  restrict in any way the rights of the
Company or any Company Affiliate to terminate a Participant's  employment at any
time for any reason, with or without cause.

       (c) Withholding. If  and to the extent  that any stock purchases or sales
under this Plan are subject to  Federal,  state or local  taxes,  the Company is
authorized to withhold all applicable  taxes from shares issuable under the Plan
or from other compensation payable to Participant.

       (d) Governing Law. The  validity, construction, interpretation and effect
of the Plan shall be governed and construed by and determined in accordance with
the laws of the state of Delaware, without giving effect to the conflict of laws
provisions thereof.