EXHIBIT 4.21

                             DECLARATION OF TRUST
                                      OF
                         STATE STREET CAPITAL TRUST II


         This DECLARATION OF TRUST, dated as of March 25, 1998, between State
Street Corporation, a Massachusetts corporation, as "Depositor," The First
National Bank of Chicago, as "Property Trustee", First Chicago Delaware Inc., as
"Delaware Trustee" and Romano I. Peluso and James E. Murphy, as "Administrative
Trustees" (collectively, the "Trustees"). The Depositor and the Trustees hereby
agree as follows:

         1.   The trust created hereby shall be known as State Street Capital
Trust II (the "Trust"), in which name the Trustees, or the Depositor to the
extent provided herein, may conduct the business of the Trust, make and execute
contracts, and sue and be sued.

         2.   The Depositor hereby assigns, transfers, conveys and sets over to
the Trust the sum of $10, which amount shall constitute the initial trust
estate. It is the intention of the parties hereto that the Trust created hereby
constitute a business trust under Chapter 38 of Title 12 of the Delaware Code,
12 Del. C. ss. 3801 et seq. (the "Business Trust Act"), and that this document
constitutes the governing instrument of the Trust. The Trustees are hereby
authorized and directed to execute and file a certificate of trust with the
Delaware Secretary of State in accordance with the provisions of the Business
Trust Act.

         3.   The Depositor and the Trustees will enter into an Amended and
Restated Trust Agreement, satisfactory to each such party and having
substantially the terms described in the Prospectus (as defined below), to
provide for the contemplated operation of the Trust created hereby and the
issuance of the Capital Securities and Common Securities referred to therein.
Prior to the execution and delivery of such amended and restated Declaration of
Trust, the Trustees shall not have any duty or obligation hereunder or with
respect to the trust estate, except as otherwise required by applicable law or
as may be necessary to obtain prior to such execution and delivery any licenses,
consents or approvals required by applicable law or otherwise.

         4.   The Depositor and the Trustees hereby authorize and direct the
Depositor, as the sponsor of the Trust, (i) to prepare and distribute any
prospectus or supplemental prospectus on behalf of the Trust, including the
prospectus relating to the Capital Securities of the Trust and certain other
securities (the "Prospectus") and any necessary or desirable amendments thereto
(including any exhibits contained therein or forming a part thereof); (ii) to
file and execute on behalf of the Trust such applications, reports, surety
bonds, irrevocable consents, appointments of attorney for service of process and
other papers and documents as the

 
Depositor, on behalf of the Trust, may deem necessary or desirable to register
the Capital Securities under, or obtain for the Capital Securities an exemption
from, the securities or "Blue Sky" laws; (iii) to execute on behalf of the Trust
such underwriting or purchase agreements with one or more underwriters,
purchasers or agents relating to the offering of the Capital Securities as the
Depositor, on behalf of the Trust, may deem necessary or desirable; and (iv) to
execute on behalf of the Trust any and all documents, papers and instruments as
may be desirable in connection with any of the foregoing. If any filing referred
to in clauses (i) or (ii) above is required by law or by the rules and
regulations of applicable governmental agency, self-regulatory organization or
other person or organization to be executed on behalf of the Trust by one of the
Trustees, the Depositor and any of the Trustees appointed pursuant to Section 6
hereof are hereby authorized to join in any such filing and to execute on behalf
of the Trust any and all of the foregoing; it being understood that The First
National Bank of Chicago and First Chicago Delaware Inc., in their capacity as
Trustees of the Trust, shall not be required to join in any such filing or
execute on behalf of the Trust any such document unless required by any such
law, rule or regulation.

         5.   This Declaration of Trust may be executed in one or more 
counterparts.

         6.   The number of Trustees initially shall be four (4) and thereafter
the number of Trustees shall be such number as shall be fixed from time to time
by a written instrument signed by the Depositor which may increase or decrease
the number of Trustees; provided, however, that to the extent required by the
Business Trust Act, one Trustee shall either be a natural person who is a
resident of the State of Delaware or, if not a natural person, an entity which
has its principal place of business in the State of Delaware and otherwise meets
the requirements of applicable Delaware law. Subject to the foregoing, the
Depositor is entitled to appoint or remove without cause any of the Trustees at
any time. Any of the Trustees may resign upon thirty days' prior notice to the
Depositor; provided, however, that such notice shall not be required if it is
           --------  -------     
waived by the Depositor.

         7.   First Chicago Delaware Inc., in its capacity as Trustee, shall not
have any of the powers or duties of the Trustees set forth herein (except as may
be required under the Business Trust Act) and shall be a Trustee of the Trust
for the sole purpose of satisfying the requirements of Section 3807 of the
Business Trust Act.

         8.   This Declaration of Trust shall be governed by, and construed in
accordance with, the laws of the State of Delaware (without regard to conflict
of laws principles).

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         IN WITNESS WHEREOF, the parties hereto have caused this Declaration of
Trust to be duly executed as of the day and year first above written.


                                      STATE STREET CORPORATION,
                                      as Depositor


                                      By: /s/ Rex S. Schuette
                                         ------------------------------------
                                         Name:  Rex S. Schuette
                                         Title: Senior Vice President and
                                                 Chief Accounting Officer


                                      THE FIRST NATIONAL BANK OF CHICAGO,
                                      as Trustee


                                      By: /s/ John R. Prendiville
                                         ------------------------------------
                                         Name:  John R. Prendiville
                                         Title: Vice President


                                      FIRST CHICAGO DELAWARE INC.,
                                      as Trustee


                                      By: /s/ John R. Prendiville
                                         ------------------------------------
                                         Name:  John R. Prendiville
                                         Title: Vice President


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                                         Romano I. Peluso
                                         as Administrative Trustee

                                         /s/ Romano I. Peluso
                                         ------------------------------------


                                         James E. Murphy
                                         as Administrative Trustee

                                         /s/ James E. Murphy
                                         ------------------------------------


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