<PAGE>
                       LIMITED LIABILITY COMPANY AGREEMENT

                                       of

                           WESTFIELD PARTNERS, L.L.C.



<PAGE>
<TABLE>
<S>                                                                           <C>
1. DEFINITIONS..................................................................1
        1.1.     "Act"..........................................................1
        1.2.     "Affiliate"....................................................1
        1.3.     "Agreement"....................................................1
        1.4.     "Capital Account"..............................................1
        1.5.     "Capital Contribution".........................................1
        1.6.     "Code".........................................................1
        1.7.     "Company Property".............................................1
        1.8.     "Former Member"................................................1
        1.9.     "Fund".........................................................2
        1.10.    "Investment Income (Loss)".....................................2
        1.11.    "Manager"......................................................2
        1.12.    "Member".......................................................2
        1.13.    "Operating Income (Loss)"......................................2
        1.14.    "Person".......................................................2
        1.15.    "Profit Sharing Income"........................................2
        1.16.    "Term".........................................................2
        1.17.    "Termination"..................................................2

2. ORGANIZATION.................................................................2
        2.1.     PURPOSE........................................................2
        2.2.     COMPANY NAME...................................................3
        2.3.     OPERATING NAME.................................................3
        2.4.     PRINCIPAL PLACE OF BUSINESS....................................3
        2.5.     TERM...........................................................3

3. CAPITAL ACCOUNTS.............................................................3
        3.1.     CAPITAL ACCOUNTS...............................................3

4. CAPITAL CONTRIBUTIONS AND STATUS OF MEMBERS..................................3
        4.1.     CAPITAL CONTRIBUTIONS..........................................3
        4.2.     STATUS OF MEMBERS..............................................4

             4.2.1.    LIMITED LIABILITY........................................4
             4.2.2.    ROLE OF MEMBER...........................................4
             4.2.3.    DEATH OF MEMBER..........................................4

5. CHARGES AND EXPENSES OF COMPANY..............................................4
        5.1.     EXPENSES RELATING TO THIS AGREEMENT............................4
        5.2.     EXPENSES OF OPERATION..........................................4

</TABLE>

                                      -ii-


<PAGE>


<TABLE>
<S>                                                                           <C>
6. ACCOUNTING FOR PROFITS AND LOSSES.............................................4
        6.1.     BOOKS AND RECORDS...............................................4
        6.2.     PROFIT SHARING INCOME...........................................4
        6.3.     INVESTMENT INCOME OR LOSS.......................................5
        6.4.     OPERATING INCOME OR LOSS........................................5
        6.5.     DISTRIBUTIONS TO NON-MEMBERS....................................5
        6.6.     NO RIGHT TO COMPANY'S PROFIT SHARING............................5
        6.7.     TAX ALLOCATIONS.................................................5
        6.8.     TAX MATTERS PARTNER.............................................6

7. DISTRIBUTIONS FROM CAPITAL ACCOUNTS...........................................6
        7.1.     MANDATORY DISTRIBUTIONS.........................................6
        7.2.     DISCRETIONARY REDEMPTIONS.......................................6

8. RIGHTS, POWERS AND OBLIGATIONS OF THE MANAGER.................................6
        8.1.     INDEPENDENT ACTIVITIES..........................................6
        8.2.     DUTIES..........................................................6
        8.3.     LIABILITY OF THE MANAGER........................................7
        8.4.     REMOVAL OR WITHDRAWAL OF THE MANAGER............................7

9. ADDITIONAL MEMBERS; REMOVAL OR WITHDRAWAL OF MEMBERS; TRANSFERS...............7
        9.1.     ADMISSION OF ADDITIONAL MEMBERS.................................7
        9.2.     REMOVAL OF MEMBERS..............................................7
        9.3.     WITHDRAWAL......................................................7
        9.4.     PAYMENTS TO FORMER MEMBERS......................................7
        9.5.     TRANSFER OF MEMBERSHIP INTEREST.................................8

10. DISSOLUTION AND WINDING UP OF THE COMPANY....................................8
       10.1.    DISSOLUTION OF THE COMPANY.......................................8
       10.2.    ADMISSION OF A SUBSTITUTE MANAGER................................8
       10.3.    RIGHT TO CONTINUE................................................9
       10.4.    WINDING UP OF THE COMPANY........................................9

11. POWER OF ATTORNEY............................................................9
       11.1.    POWER OF ATTORNEY FOR THE MANAGER................................9
       11.2.    IRREVOCABILITY; EXERCISE; SURVIVAL..............................10

12. INDEMNIFICATION OF THE MANAGER..............................................10
       12.1.    EXCLUSION OF LIABILITY FOR RETURN OF CAPITAL CONTRIBUTIONS......10
       12.2.    LIMITATION ON LIABILITY OF MANAGER; INDEMNIFICATION..,,,,,......10

</TABLE>

                                     -iii-



<PAGE>


<TABLE>
<S>                                                                           <C>

13. MISCELLANEOUS...............................................................11
       13.1.    AMENDMENTS......................................................11
       13.2.    INTERESTED TRANSACTIONS.........................................11
       13.3.    VALUATION.......................................................12
       13.4.    ARBITRATION.....................................................12
       13.5.    SECTION CAPTIONS................................................12
       13.6.    SEVERABILITY....................................................12
       13.7.    MASSACHUSETTS LAW...............................................12
       13.8.    WAIVER OF ACTION FOR DISSOLUTION OR PARTITION...................12
       13.9.    COUNTERPART EXECUTION...........................................13
       13.10.   PARTIES IN INTEREST.............................................13
       13.11.   TIME............................................................13
       13.12.   GENDER..........................................................13
       13.13.   AGENT FOR SERVICE OF PROCESS....................................13
       13.14.   INTEGRATED AGREEMENT............................................13
</TABLE>


                                      -iv-

<PAGE>





                       LIMITED LIABILITY COMPANY AGREEMENT

                                       of

                           WESTFIELD PARTNERS, L.L.C.

         THIS LIMITED LIABILITY COMPANY AGREEMENT dated as of July __, 1999 is
executed by and among WESTFIELD CAPITAL MANAGEMENT COMPANY, INC., a
Massachusetts corporation, as the Manager, and the Members set forth on Schedule
I as the initial Members. The Manager may, in its sole discretion, make changes
in the Company's books and records to reflect the admission, substitution, or
withdrawal of any Member.

1. DEFINITIONS.  As used herein, the following terms shall have the following
meanings:

                  1.1. "Act" means the Massachusetts Limited Liability Company
         Act, as such Act may be amended from time to time.

                  1.2. "Affiliate" means any Person (a) directly or indirectly
         owning, controlling or holding with power to vote any of the
         outstanding voting securities of another Person; (b) any of whose
         outstanding voting securities are directly or indirectly owned,
         controlled or held with power to vote by another Person; (c) directly
         or indirectly controlling, controlled or under common control with
         another Person or Persons; or (d) who is an officer, director, partner,
         member, spouse, parent or child of another Person.

                  1.3. "Agreement" means this Limited Liability Company
         Agreement, as amended from time to time.

                  1.4. "Book Capital Account" shall have the meaning assigned to
         it in the agreement of limited partnership, limited liability company
         agreement or similar governing agreement, as applicable, for each Fund

                  1.5. "Capital Account" means the account described in
         Section 3.1.

                  1.6. "Capital Contribution" means the amount contributed from
         time to time to the capital of the Company by the Manager or a Member.

                  1.7. "Code" means the Internal Revenue Code of 1986, as
         amended from time to time.


<PAGE>



                  1.8. "Company" means the limited liability company formed by
         this agreement.

                  1.9.  "Company Property" means any interest in real or
         personal property, tangible or intangible, acquired by the Company.

                  1.10. "Former Member" shall have the meaning set forth in
         Section 9.4.

                  1.11. "Fund" means any limited partnership, limited liability
         company, business trust or other investment vehicle, whether now
         existing or hereinafter formed, in which the Company has a profit
         sharing interest.

                  1.12. "Investment Income (Loss)" shall mean, with respect to
         any period, all net income or loss (including unrealized income or
         loss) attributable to the Company's investments in any Fund that is
         exempt from the registration requirements of the Investment Company Act
         of 1940, as amended, in reliance on Sections 3(c)(1) or 3(c)(7) under
         such Act, other than Profit Sharing Income and income attributable to
         such the Company's Profit and Loss Accounts.

                  1.13. "Manager" means Westfield Capital Management Company,
         Inc., and any substitute, successor or additional Manager approved as
         provided by this Agreement; the business address of the aforenamed
         Manager is One Financial Center, Boston, Massachusetts 02111.

                  1.14. "Member" means each Person listed from time to time as a
         Member in the Company's books and records.

                  1.15. "Operating Income (Loss)" shall mean, with respect to
         any period, all net income or loss (including unrealized income or
         loss) other than Profit Sharing Income, Investment Income or Loss, and
         income allocated to a Profit and Loss Account.

                  1.16. "Person" means any individual, estate, trust,
         partnership, corporation, limited liability company, association or
         other legal entity.

                  1.17. "Profit and Loss Account" shall have the meaning
         assigned to it in the agreement of limited partnership, limited
         liability company agreement or similar governing agreement, as
         applicable, for each Fund.

                  1.18. "Profit Sharing Income" shall mean, with respect to any
         period, the net increase, if any, in the Company's "Performance
         Account" in each of the


<PAGE>


          Funds (as such term is defined in the agreement of limited
          partnership, limited liability company agreement or similar governing
          agreement, as applicable, for each Fund) which is reallocated to the
          Book Capital Account of the Company, or any similar amount which is
          reallocated to the Book Capital Account of the Company from a similar
          profit sharing account the Company may have in the future in any Fund.

                  1.19. "Term" shall have the meaning set forth in Section 2.5.

                  1.20.  "Termination" shall have the meaning set forth in
         Section 9.4.

2. ORGANIZATION.

                  2.1. PURPOSE. The purpose for which the Company is formed is
         to serve as a general partner, manager or in similar capacities of such
         Funds as the Manager in its discretion may determine. The Company shall
         also have as additional purposes all lawful activities related to or
         incidental to such purpose, and such other lawful purposes as the
         Manager may from time to time determine.

                  2.2. COMPANY NAME.  The name of the Company shall be
         Westfield Partners, L.L.C.

                  2.3. OPERATING NAME. The activities of the Company may be
         conducted under any name chosen by the Manager and the Manager may, in
         its sole discretion, from time to time change the name of the Company.

                  2.4. PRINCIPAL PLACE OF BUSINESS. The principal place of
         business of the Company shall be at One Financial Center, Boston,
         Massachusetts 02111, or at such other place as the Manager may from
         time to time determine.

                  2.5. TERM. The term ("Term") of the Company commenced upon the
         filing in the office of the Secretary of The Commonwealth of
         Massachusetts of the Certificate of Organization of the Company, and
         shall thereafter be perpetual, unless terminated sooner pursuant to
         this Agreement.

3. CAPITAL ACCOUNTS.

                  3.1. CAPITAL ACCOUNTS. The interest of the Manager and each
         Member in the Company shall be expressed in terms of a Capital Account.
         The Capital Account of the Manager and each Member shall be increased
         by Capital Contributions and Profit Sharing Income, if any, allocated
         to the Manager or


                                      -3-
<PAGE>


         such Member pursuant to Section 6.2, Investment Income, if any,
         allocated to the Manager or such Member pursuant to Section 6.3, and
         Operating Income, if any, allocated to the Manager or such Member
         pursuant to Section 6.4; and shall be decreased by Investment Loss, if
         any, allocated to the Manager or such Member pursuant to Section 6.3,
         Operating Loss, if any, allocated to the Manager or such Member
         pursuant to Section 6.4, distributions to such Member pursuant to
         Sections 7.1 and 7.2, and redemptions of such Member's interest in the
         Company pursuant to Section 9.4.

                  3.2. PROFIT AND LOSS ACCOUNT DEFICITS. If, upon liquidation of
         any Fund, the Company's Profit and Loss Account has a negative balance,
         the Manager shall be obligated to make additional capital contributions
         to the Company in cash equal to such negative balance.

4. CAPITAL CONTRIBUTIONS AND STATUS OF MEMBERS.

                  4.1. CAPITAL CONTRIBUTIONS. As of the date hereof, the Manager
         and the Members have made the initial Capital Contributions (the
         "Initial Capital Contribution") with respect to each Fund as set forth
         on Schedule I hereto, as such schedule may be amended from time to
         time. No Member shall be required to make any additional contributions
         to the capital of the Company.

                  4.2. STATUS OF MEMBERS.

                           4.2.1. LIMITED LIABILITY. Except as provided in the
                  Act, a Member as such shall not be liable for the debts and
                  obligations of the Company. The creditors of the Company shall
                  have no recourse against any Member.

                           4.2.2. ROLE OF MEMBER. A Member as such shall not
                  take part in or interfere in any manner with the conduct or
                  control of the activities of the Company and shall have no
                  right or authority to act for or bind the Company.

                           4.2.3. DEATH OF MEMBER. Subject to Section 9.4
                  hereof, on the death of a Member, for the purpose of settling
                  his estate, his executor or administrator shall have all the
                  rights of a Member and such rights to assign or have redeemed
                  his interest as the Member had before his death.


                                      -4-
<PAGE>

5. CHARGES AND EXPENSES OF COMPANY.

                  5.1. EXPENSES RELATING TO THIS AGREEMENT. The Company shall
         reimburse the Manager for expenses borne, incurred or advanced by the
         Manager on behalf of the Company on account of the preparation of this
         Agreement, including attorneys' fees, accountants' fees, and other
         expenses incident thereto. Such expenses which are not paid by the
         Manager shall be paid as a debt of the Company.

                  5.2. EXPENSES OF OPERATION. The Company shall pay, or shall
         reimburse the Manager for, such expenses incurred or advanced in the
         operation or management of the Company as the Manager shall deem to be
         reasonable and necessary.

6. ACCOUNTING FOR PROFITS AND LOSSES.

                  6.1. BOOKS AND RECORDS. Appropriate records and books of
         account shall be kept according to generally accepted accounting
         principles or such other basis of accounting as may be selected by the
         Manager, at the principal place of business of the Company, and each
         Member shall have access to all records and books of account and the
         right to receive copies thereof. The Company shall use a fiscal year
         ending on December 31 in reporting its income and expenses.

                  6.2. PROFIT SHARING INCOME.

                           6.2.1. As of the last business day of each fiscal
                  year for such fiscal year, the Manager shall allocate among
                  the Capital Accounts of the Members other than the Manager, in
                  the Manager's sole discretion, 65 percent of the Profit
                  Sharing Income attributable to each Fund (or such lesser
                  amount pursuant to Section 6.5). The amount of such
                  allocation, if any, to the Capital Account of any particular
                  Member is to be determined in the sole discretion of the
                  Manager.

                           6.2.2. As of the last business day of each fiscal
                  year for such fiscal year, the Manager shall allocate to the
                  Capital Account of the Manager 35 percent of the Profit
                  Sharing Income.

                  6.3. INVESTMENT INCOME OR LOSS. As of the last business day of
         each fiscal year, Investment Income or Loss, if any, shall be allocated
         to the Capital Accounts of the Manager and the Members in proportion to
         each Manager and Member's Capital Account balances as of the last day
         of such fiscal year (determined before any other allocations of profit
         and loss) minus such Manager and Member's Initial Capital
         Contributions. If new Members were


                                      -5-
<PAGE>


          admitted during a fiscal year, or if one or more Members withdraws
          during a fiscal year, the Manager shall allocate amounts representing
          Investment Income or Loss so as to take into account the varying
          interests of the Manager and the Members in the Company during such
          year.

                  6.4. OPERATING INCOME OR LOSS. As of the last business day of
         each fiscal year, Operating Income or Loss, if any, shall be allocated
         to the Capital Accounts of the Manager and the Members in proportion to
         their Capital Account balances as of the last day of such fiscal year.
         If new Members were admitted during a fiscal year, or if one or more
         Members withdraws during a fiscal year, the Manager shall allocate
         amounts representing Operating Income or Loss so as to take into
         account the varying interests of the Manager and the Members in the
         Company during such year.

                  6.5.  DISTRIBUTIONS TO NON-MEMBERS.  As of the last business
         day of each fiscal year for such fiscal year, the Manager may
         distribute, in the Manager's sole discretion, up to 65 percent of the
         Profit Sharing Income attributable to each Fund to any Person or
         Persons. The amount of Profit Sharing Income available for allocation
         for such fiscal year pursuant to Section 6.2.1 hereof shall be reduced
         by the amount of any distribution or distributions made pursuant to
         this Section 6.5 for such fiscal year.

                  6.6. PROFIT AND LOSS ACCOUNT ALLOCATIONS.

                           6.6.1. As of the last business day of each fiscal
                  year, allocations of profit attributable to the Company's
                  Profit and Loss account in each Fund shall be made as follows:

                           (1) first, if there is a negative balance in such
                  Profit and Loss Account, 100 percent to the Manager's Capital
                  Account to the extent of the amount of profits necessary to
                  cause such Profit and Loss Account to be equal to zero;

                           (2) second, 35 percent to the Manager's Capital
                  Account and 65 percent to the Members' Capital Accounts in
                  proportion to their respective capital contributions credited
                  to such Profit and Loss Account until the amount of such
                  profits equals each Member's capital contribution credited to
                  such Profit and Loss Account; and

                           (3) third, 65 percent among the Capital Accounts of
                  the Members, allocated in the Manager's sole discretion (or
                  such lesser amount



                                      -6-
<PAGE>



                  pursuant to Section 6.5), and 35 percent to the Capital
                  Account of the Manager.

                           6.6.2. As of the last business day of each fiscal
                  year, allocations of loss attributable to the Company's Profit
                  and Loss Account in each Fund shall be made as follows:

                           (1) first, 35 percent to the Manager's Capital
                  Account and 65 percent to the Members' Capital Accounts in
                  proportion to their respective capital contributions credited
                  to such Profit and Loss Account until the amount of such loss
                  equals each Member's capital contribution credited to such
                  Profit and Loss Account; and

                           (2) second, 100 percent to the Manager's Capital
                  Account.

                  6.7. NO RIGHT TO COMPANY'S PROFIT SHARING. No Member shall
         have any right to any part of the Company's Profit Sharing Income for
         any fiscal year, except by virtue of allocations pursuant to Section
         6.2 hereof.

                  6.8. TAX ALLOCATIONS. The income, gains, losses, deductions
         and credits of the Company shall be allocated for federal, state and
         local income tax purposes among the Manager and the Members so as to
         reflect, in the judgment of the Manager, the interests of the Members
         in the Company set forth in this Agreement. The Manager, in
         consultation with the Company's tax advisor, is authorized (i) to
         select such tax allocation methods as may in the Manager's judgment be
         appropriate to satisfy the requirements of section 704(c) of the Code;
         (ii) to interpret and apply the allocation provisions hereof as
         providing for a "qualified income offset", "minimum gain chargeback"
         and such other allocation principles as may be required under section
         704 of the Code and applicable regulations (provided that if such
         principles are applied in making allocations hereunder, subsequent
         allocations shall be made so as to reverse, to the extent possible in
         the Manager's judgment, the effect of the application of such
         principles); (iii) to make special allocations of income or loss to
         the Manager and Members who redeem all or a portion of their Capital
         Account balance; (iv) to determine the allocation of specific items of
         income, gain, loss, deduction and credit of the Company; and (v) to
         vary any and all of the foregoing allocation provisions to the extent
         necessary in the judgment of the Manager to comply with section 704 of
         the Code and applicable regulations. The Manager shall have the power
         and authority to make all accounting, tax and financial reporting
         determinations and decisions with respect to the Company.




                                      -7-
<PAGE>

                  6.9. TAX MATTERS PARTNER. The "tax matters partner" of the
         Company shall be the Manager or such other Person as the Manager may
         from time to time designate in writing.

7. DISTRIBUTIONS FROM CAPITAL ACCOUNTS.

                  7.1. MANDATORY DISTRIBUTIONS. The Company shall, upon any
         Member's request, distribute Profit Sharing Income, if any, and
         Investment Income, if any, allocated to such Member's Capital Account
         for a fiscal period on the day such amounts are allocated to such
         Account. Capital Accounts shall be reduced by amounts so distributed.

                  7.2. DISCRETIONARY REDEMPTIONS. Any Member may request that
         the Company redeem all or any portion of such Member's Capital Account
         as of the last business day of any fiscal month. Such redemptions shall
         be made by the Company in the sole discretion of the Manager.

8. RIGHTS, POWERS AND OBLIGATIONS OF THE MANAGER.

                  8.1. INDEPENDENT ACTIVITIES. The Manager may, notwithstanding
         the existence of this Agreement, engage in whatever activities it may
         choose, whether or not such activities are competitive with the
         activities of the Company, without having or incurring any obligation
         to offer any interest in such activities to the Company or any party
         hereto. The Manager may organize and participate as partner, manager,
         shareholder and/or adviser in one or more partnerships, limited
         liability companies or corporations which may engage in activities
         substantially identical to the activities of the Company without any
         liability therefor.

                  8.2. DUTIES.  The Manager shall devote such time to the
         activities of the Company as it determines is necessary for the
         efficient carrying on thereof.

                  8.3. LIABILITY OF THE MANAGER. The Manager shall be generally
         liable for the debts and obligations of the Company; provided, however,
         that any such liability shall be satisfied first out of the assets of
         the Company.

                  8.4. REMOVAL OR WITHDRAWAL OF THE MANAGER. A Manager shall
         cease to be the Manager of the Company:

                           8.4.1. Upon the withdrawal by a Manager upon 30 days'
                  prior written notice to the Members;



                                      -8-
<PAGE>



                           8.4.2. Immediately following the dissolution of a
                  Manager in corporate, partnership or limited liability company
                  form; or

                           8.4.3. If such Manager has: (i) made an assignment
                  for the benefit of creditors; (ii) filed a voluntary petition
                  in bankruptcy; (iii) been adjudicated a bankrupt or insolvent;
                  (iv) filed a petition or answer seeking for such Manager any
                  reorganization, arrangement, composition, readjustment,
                  liquidation, dissolution or similar relief under any statute,
                  law or regulation; (v) filed an answer or other pleading
                  admitting or failing to contest the material allegations of a
                  petition filed against such Manager in any proceeding of such
                  nature; or (vi) sought, consented to or acquiesced in the
                  appointment of a trustee, receiver or liquidator of such
                  Manager or of all or any substantial part of such Manager's
                  properties.

9. ADDITIONAL MEMBERS; REMOVAL OR WITHDRAWAL OF MEMBERS; TRANSFERS.

                  9.1. ADMISSION OF ADDITIONAL MEMBERS. The Manager shall have
         the power to admit additional Members to the Company at any time in its
         sole discretion.

                  9.2. REMOVAL OF MEMBERS. The Manager shall have the power to
         remove any Member from the Company at any time in its sole discretion.
         Such removed Member's interest in the Company shall be determined in
         the same manner as in Section 9.4.

                  9.3. WITHDRAWAL. Any Member may withdraw from the Company upon
         7 days' prior written notice to the Manager.

                  9.4. PAYMENTS TO FORMER MEMBERS. Upon the removal, withdrawal,
         death or bankruptcy (each, a "Termination") of any Member (each, a
         "Former Member"):

                           9.4.1. The Manager may, in its sole discretion,
                  allocate amounts to the Capital Account of the Former Member
                  pursuant to Section 6 hereof, the amount of such allocation,
                  if any, to be determined by the Manager in its sole
                  discretion. Such amounts, if any, shall be withdrawn by the
                  Former Member pursuant to Section 7.1 hereof as if such Former
                  Member were a Member.

                           9.4.2. The Former Member will be distributed an
                  amount equal to such Member's Capital Account balance, net of
                  reasonable



                                      -9-
<PAGE>


                   reserves determined in the Manager's sole discretion, in
                   complete redemption of such Member's interest in the Company
                   on a date (following the date of Termination) to be
                   determined in the sole discretion of the Manager.

                  9.5. TRANSFER OF MEMBERSHIP INTEREST. No Member shall sell,
         assign, transfer, pledge or otherwise encumber his or its interest in
         the Company, in its assets or in the profits thereof, except with the
         consent of the Manager, which may be withheld in the Manager's sole
         discretion.

10. DISSOLUTION AND WINDING UP OF THE COMPANY.

                  10.1. DISSOLUTION OF THE COMPANY. The Company shall be
         dissolved upon the first to occur of any of the following events:

                           10.1.1. The Manager ceases to be a Manager pursuant
                  to Section 8.4 unless within 90 days after the occurrence of
                  such event a majority in number of the Members agree in
                  writing to continue the business of the Company and to the
                  appointment, effective as of the date of such event, of a
                  substitute Manager to be admitted pursuant to Section 10.2;

                           10.1.2. The vote so to do of the Manager and a
                  majority in number of the Members; or

                           10.1.3. When required by the Act.

                  10.2. ADMISSION OF A SUBSTITUTE MANAGER. If the Manager
          ceases to be the Manager and a substitute Manager is to be admitted
          by the Members pursuant to Section 10.1.1 any Member may, promptly
          after the agreement of the Members to continue as provided in
          Section 10.1.1, nominate a Person for admission as a substitute
          Manager. Such Person shall not become the Manager unless (i) such
          Person is admitted by written consent of a majority in number of
          the Members and (ii) such Person has consented in writing to be
          bound by the terms of this Agreement and the Company's Certificate
          of Organization. If such proposed Manager is not admitted, any Member
          may as soon as practicable thereafter nominate another substitute
          Manager until a substitute Manager is admitted or the Company has
          been dissolved pursuant to Section 10.1.2 hereof.

                  10.3. RIGHT TO CONTINUE. The Company shall not be dissolved
         upon the death, retirement, resignation, removal, expulsion, bankruptcy
         or dissolution of


                                      -10-
<PAGE>


          any Member, or the occurrence of any other event that terminates the
          continued membership of any Member in the Company.

                  10.4. WINDING UP OF THE COMPANY. Upon dissolution of the
         Company, the books of the Company shall be closed and appropriate
         debits and credits to the Capital Accounts of the Manager and the
         Members shall be made to reflect the allocation of profits and loss
         attributable to the liquidation of the Company's assets (including, in
         the case of assets distributed in kind, the allocation of profit and
         loss that would occur if such assets of the Company were sold at their
         fair market value). The Manager, or if there is no Manager, a trustee
         elected by a majority in number of the Members, shall take full account
         of the Company's assets and liabilities and the assets shall be
         liquidated as promptly as is consistent with obtaining the fair market
         value thereof, and the proceeds therefrom to the extent sufficient
         therefor (or any unsold assets which shall be valued at their fair
         market value), shall be applied and distributed in the following order,
         or as otherwise required to comply with the Act:

                           10.4.1. To creditors, including the Manager and
                  Members who are creditors, to the extent permitted by law, in
                  satisfaction of liabilities of the Company other than
                  liabilities for distributions to the Manager and Members in
                  their capacity as the Manager and Members, respectively;

                           10.4.2. To Members and Former Members in satisfaction
                  of liabilities for distributions provided for hereunder; and

                           10.4.3. To the Manager and Members in accordance with
                  their respective Capital Accounts at the time of the
                  dissolution.



                                      -11-
<PAGE>

11. POWER OF ATTORNEY.

                  11.1. POWER OF ATTORNEY FOR THE MANAGER. Provided that the
          action to be taken is in accordance with the terms of this Agreement,
          each Member hereby makes, constitutes and appoints the Manager and
          each Person who shall hereafter become a Manager, with full power of
          substitution and resubstitution, his true and lawful attorney in his
          name, place and stead and for his use and benefit to sign, execute,
          certify, acknowledge, swear to, file and record this Agreement and the
          Company's Certificate of Organization, and to sign, execute, certify,
          acknowledge, swear to, file and record any and all instruments
          amending this Agreement and the Company's Certificate of Organization,
          as now or hereafter amended, that the Manager in its sole discretion
          deems appropriate including, without limitation, agreements or other
          instruments or documents (1) to reflect the exercise by the Manager of
          any of the powers granted to it under this Agreement; (2) to reflect
          any amendments made to this Agreement and the Company's Certificate of
          Organization pursuant to this Agreement; (3) to reflect the withdrawal
          of any Member, in the manner prescribed in this Agreement; and (4) to
          reflect actions which may be required of the Company or the Members by
          the laws of any jurisdiction. Each Member authorizes such
          attorney-in-fact to take any further action which such
          attorney-in-fact shall consider necessary or advisable in connection
          with any of the foregoing, hereby giving such attorney-in-fact full
          power and authority to do and perform each and every act or thing
          whatsoever requisite or advisable to be done in and about the
          foregoing as fully as such Member might or could do if personally
          present, hereby ratifying and confirming all that such
          attorney-in-fact shall lawfully do or cause to be done by virtue
          hereof.

                  11.2. IRREVOCABILITY; EXERCISE; SURVIVAL. The power of
         attorney granted pursuant to Section 11.1 hereof:

                           11.2.1. Is a special power of attorney coupled with
                  an interest and is irrevocable;

                           11.2.2. May be exercised by such attorney-in-fact by
                  listing all of the Members executing any agreement,
                  certificate, instrument or documents with the single signature
                  of such attorney-in-fact acting as attorney-in-fact for all of
                  them; and

                           11.2.3. Shall survive the delivery of an assignment
                  by a Member of the whole or a portion of his interest in the
                  Company, except that where the purchaser, transferee or
                  assignee thereof has the right to be, or with consent of the
                  Manager is admitted as, a substituted Member, the power of
                  attorney shall survive the delivery of such assignment for the
                  sole purpose of enabling such attorney-in-fact to execute,
                  acknowledge and file any such agreement, certificate,
                  instrument or document necessary to effect such substitution.


                                      -12-
<PAGE>

12. INDEMNIFICATION OF THE MANAGER.

                  12.1. EXCLUSION OF LIABILITY FOR RETURN OF CAPITAL
         CONTRIBUTIONS. Anything in this Agreement to the contrary
         notwithstanding, neither the Manager nor any of its Affiliates, nor any
         agent or other Person authorized to act for the Company, shall be
         personally liable for the return of all or any portion of any Member's
         Capital Contribution, it being expressly understood that any such
         return shall be made solely from Company assets.

                  12.2. LIMITATION ON LIABILITY OF MANAGER; INDEMNIFICATION.
         Anything in this Agreement to the contrary notwithstanding, the Manager
         shall not in any event be liable, responsible or accountable in damages
         or otherwise to any of the Members or to the Company for, and the
         Company shall indemnify and save harmless the Manager from, any losses
         or damages incurred by reason of any act or omission performed or
         omitted to be performed by the Manager, if the Manager, in good faith,
         determined that such act was in the best interest of the Company,
         provided that the foregoing shall not relieve the Manager of liability
         or indemnity and save the Manager harmless for the Manager's willful
         misconduct or gross negligence. This limitation of liability, indemnity
         and hold harmless is for the benefit of the Manager and its Affiliates,
         and their respective directors, officers and employees. In particular,
         and without limitation of the foregoing, the Manager shall be entitled
         to indemnification by the Company against the reasonable expenses,
         including attorneys' fees, actually and necessarily incurred by the
         Manager in connection with the defense of any suit or action to which
         the Manager may be made a party by reason of having acted as a Manager,
         to the fullest extent permitted by the Act. The Manager shall be
         entitled to receive, upon application therefor, advances to cover the
         costs of defending any claim or action against it; provided that such
         advances shall be repaid to the Company, without interest, if the
         Manager is found by a court of competent jurisdiction to have violated
         the provisions of this Agreement in such a manner as to not entitle
         such Manager to payment of such costs.

13. MISCELLANEOUS.

                  13.1. AMENDMENTS. The Manager may amend any provision of this
         Agreement without the necessity of the consent of any of the Members;
         PROVIDED, HOWEVER, that an amendment which would (i) result in the loss
         of any Member's limited liability, (ii) require any Member to
         contribute additional capital other


                                      -13-
<PAGE>



         than as specifically set forth herein, or (iii) alter the provisions
         of this Section 13.1 shall not be adopted and effective unless it
         receives the affirmative approval of all Members materially adversely
         affected by such amendment.

                  13.2. INTERESTED TRANSACTIONS. Each of the parties to this
          Agreement hereby (a) expressly acknowledges that certain transactions
          contemplated by this Agreement and powers delegated to the Manager
          hereunder, including, without limitation, the Manager's right to make
          certain allocations under Section 6.2, may constitute interested or
          self-dealing transactions between the Manager and one or more of its
          Affiliates, (b) expressly acknowledges that the Manager may, and
          specifically authorizes it (i) to allocate such amounts as it in its
          sole discretion may determine, to the Capital Accounts of the Manager
          and its Affiliates pursuant to Section 6.2 and (ii) to distribute such
          amounts as it in its sole discretion may discretion may determine to
          Persons who may be Affiliates of the Manager pursuant to Section 6.5;
          and each of the parties to this Agreement hereby agrees that any such
          allocations or distributions will not constitute a breach of fiduciary
          duty by the Manager, and (c) waives, to the fullest extent permitted
          by law, any rights or claims such party may have against the Manager
          or its Affiliates arising in connection with the consummation of such
          transactions or exercise of such powers and that are based on conflict
          of interest, breach of fiduciary duty or any similar grounds;
          PROVIDED, HOWEVER, that such waiver shall be effective only to the
          extent that the Manager or its Affiliates have exercised reasonable
          business judgment in the consummation of such transactions or exercise
          of such powers.

                  13.3. VALUATION. Whenever for purposes of this Agreement it is
         necessary to determine the value of the Company Property, such value
         shall be determined by the Manager acting in good faith. Any such
         determination by the Manager shall be conclusive and binding on all
         Members.

                  13.4. ARBITRATION. The Members and the Manager hereby agree
         to submit all controversies, claims and matters of difference to
         arbitration in Boston, Massachusetts, according to the rules and
         practices of the American Arbitration Association in force at the time
         of submission. Such arbitration shall be before a panel of 3
         arbitrators one of whom is to be selected by each party and a third
         selected by the arbitrators chosen by the parties. This agreement to
         arbitrate shall be specifically enforceable. Without limiting the
         generality of the foregoing, all questions relating to the breach of
         any obligation, warranty or condition hereunder, and all questions as
         to whether the right to arbitrate exists shall be considered
         controversies for the purposes of this section. The award rendered in
         such proceedings shall be final and binding on all parties to the
         extent permitted by Massachusetts law and may be



                                      -14-
<PAGE>


         entered as a judgment in any court of competent jurisdiction. This
         paragraph shall not apply, however, to any cause of action which may
         arise under federal or state securities laws.

                  13.5. SECTION CAPTIONS. Section and other captions contained
         in this Agreement are for reference purposes only and are in no way
         intended to describe, interpret, define or limit the scope, extent or
         intent of this Agreement or any provision hereof.

                  13.6. SEVERABILITY. Every provision of this Agreement is
         intended to be severable. If any term or provision hereof is illegal or
         invalid for any reason whatsoever, such illegality or invalidity shall
         not affect the validity of the remainder of this Agreement.

                  13.7. MASSACHUSETTS LAW. This Agreement shall be governed,
         construed and enforced in accordance with the laws of The Commonwealth
         of Massachusetts, without giving effect to the choice of law principles
         thereof.

                  13.8. WAIVER OF ACTION FOR DISSOLUTION OR PARTITION. Each
         party hereto irrevocably waives during the Term of the Company any
         right to apply for dissolution of the Company. Each party hereto also
         irrevocably waives during the Term of the Company and during the period
         of its liquidation following any dissolution, any right which such
         party may have to maintain any action for partition with respect to any
         of the Company Property.

                  13.9. COUNTERPART EXECUTION. This Agreement may be executed in
         any number of counterparts with the same effect as if all the parties
         hereto had signed the same document, each of which counterparts shall
         be an original and all of which shall constitute but one and the same
         Agreement. The Subscription Agreement of each Member shall, upon
         acceptance of such Subscription Agreement by the Manager and admission
         of the subscriber as a Member in the Company, be deemed part of this
         Agreement, is hereby incorporated herein by reference and may be
         attached with the Subscription Agreements of all other subscribers to a
         master copy of this Agreement, which shall constitute the entire
         executed Limited Liability Company Agreement.

                  13.10. PARTIES IN INTEREST. Each and every covenant, term,
         provision and agreement herein contained shall be binding upon and
         inure to the benefit of the heirs, successors, legal representatives
         and assigns of the respective parties hereto.

                  13.11. TIME.  Time is of the essence with respect to this
         Agreement.


                                      -15-
<PAGE>


                  13.12. GENDER. All references herein to one gender also
         include, where appropriate, the other gender. Where appropriate, the
         singular includes the plural and the plural includes the singular.

                  13.13. AGENT FOR SERVICE OF PROCESS. The Manager shall be the
         Company's agent for service of process.

                  13.14. INTEGRATED AGREEMENT. This Agreement constitutes the
         entire understanding and agreement among the parties.


                                      -16-
<PAGE>

         IN WITNESS WHEREOF, this Limited Liability Company Agreement of
Westfield Partners, L.L.C. has been executed as of the date first written above.

                                     MANAGER
                                     -------
                                     Westfield Capital Management Company, Inc.



                                     By:
                                        ---------------------------------
                                     Name:  Stephen C. Demirjian
                                     Title: Senior Vice President



                                     MEMBERS
                                     -------
                                     By: Westfield Capital Management Company,
                                         Inc., as attorney-in-fact for each such
                                         Member



                                     By:
                                        ---------------------------------
                                     Name:  Stephen C. Demirjian
                                     Title:    Senior Vice President


                                      -17-
<PAGE>


                                   SCHEDULE I

                                       INITIAL CAPITAL CONTRIBUTIONS
                           -----------------------------------------------------
                           Westfield Technology Fund    Westfield Capital Growth

       MEMBERS             II Limited Partnership    Fund II Limited Partnership
       -------
Arthur J. Bauernfeind             $698.75                     $1,004.40

Stephen C. Demirjian              $698.75                     $1,004.40

C. Michael Hazard                 $698.75                     $1,004.40

William A. Muggia                 $698.75                     $1,004.40

B. Randall Watts                  $698.75                     $1,004.40



     MANAGER                    $1,881.25                     $2,704.15
     -------