Document:

EXHIBIT 4.7

                          COMMON STOCK PURCHASE WARRANT

                To Purchase __________ Shares of Common Stock of

                           Mpower Holding Corporation

          THIS COMMON STOCK PURCHASE WARRANT (the "Warrant") CERTIFIES that, for
value received, _____________ (the "Holder"), is entitled, upon the terms and
subject to the limitations on exercise and the conditions hereinafter set forth,
at any time on or after the date hereof (the "Warrant Date") and on or prior to
5:00 p.m. New York City time on the third anniversary of the Warrant Date (the
"Termination Date") but not thereafter, to subscribe for and purchase from
Mpower Holding Corporation, a corporation incorporated in the State of Delaware
(the "Company"), up to ____________ shares (the "Warrant Shares") of Common
Stock, par value $0.001 per share, of the Company (the "Common Stock"). The
purchase price of each Warrant Share (the "Exercise Price") issuable under this
Warrant shall be equal to the average weighted price per share of the Company's
Common Stock on the Warrant Date as quoted by any national or regional
securities exchange on which the Company's Common Stock is then listed or on any
interdealer or over-the counter quotation system on which the Company's common
stock is then quoted (a "Trading Market"), subject to adjustment hereunder. If
the Company's Common Stock is not then listed or quoted, the Exercise Price
shall be equal to the fair value, as determined in good faith by the Company's
Board of Directors, of a share of the Company's common stock on the Warrant
Date. The Exercise Price and the number of Warrant Shares for which the Warrant
is exercisable shall be subject to adjustment as provided herein.

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          1. Title to Warrant. Subject to compliance with applicable laws, this
Warrant is non-transferable, and may not be transferred in whole or in part, by
the Holder.

          2. Authorization of Shares. The Company covenants that all Warrant
Shares which may be issued upon the exercise of the purchase rights represented
by this Warrant will, upon exercise of the purchase rights represented by this
Warrant, be duly authorized, validly issued, fully paid and nonassessable and
free from all taxes, liens and charges in respect of the issue thereof (other
than taxes in respect of any transfer occurring contemporaneously with such
issue).

          3. Cancellation of Warrant. At any time prior to the Termination Date,
the Company reserves the right, pursuant to the terms of the Mpartner
Independent Agent Agreement, as amended (the "Agent Agreement") between the
Company and certain of its master sales agents, to cancel this Warrant prior to
its exercise upon the occurrence of any of the conditions for termination for
cause set forth in the Agent Agreement. In addition, if a customer or customers
provided by the Holder disconnect(s) the Company's service within one hundred
eighty (180) days of such customer's installation, and as a result of such
disconnect(s), a recalculation of the billings in any given month would result
in a reduction of the number of Warrant Shares for which this Warrant is
exercisable, the Company reserves the right to reduce the number of Warrant
Shares for which this Warrant is exercisable, on a pro rata basis and, if such
customer disconnect(s) result in revised billings in any given month of less
than $10,000 over that month's revenue baseline, the Company reserves the right
to cancel this Warrant.

          4. Exercise of Warrant.

               (a) Exercise of the purchase rights represented by this Warrant
     may be made at any time or times on or after the Warrant Date and on or
     before 5:00 p.m. New York City time on the Termination Date by delivery to
     the Company of a duly executed facsimile copy of the Notice of Exercise
     Form annexed hereto (or such other office or agency of the Company as it
     may designate by notice in writing to the registered Holder at the address
     of such Holder appearing on the books of the Company); provided, however,
     within 5 Trading Days of the date the Notice of Exercise is delivered to
     the Company, the Holder shall have surrendered this Warrant to the Company
     and the Company shall have received payment of the aggregate Exercise Price
     of the shares thereby purchased by wire transfer or cashier's check drawn
     on a United States bank. Certificates for shares purchased hereunder shall
     be delivered to the Holder within the earlier of (i) 10 Trading Days after
     the date on which the Notice of Exercise shall have been delivered by
     facsimile copy or (ii) 3 Trading Days from the delivery to the Company of
     each of the Notice of Exercise Form by facsimile copy, surrender of this
     Warrant and payment of the aggregate Exercise Price as set forth above
     ("Warrant Share Delivery Date"); provided, however, in the event the
     Warrant is not surrendered or the aggregate Exercise Price is not received
     by the Company within 5 Trading Days after the date on which the Notice of
     Exercise shall be delivered by facsimile copy, the Warrant Share Delivery
     Date shall be terminated or superceded to the extent that such period is
     exceeded. This Warrant shall be deemed to have been exercised on the later
     of the date

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     the Notice of Exercise is delivered to the Company by facsimile copy and
     the date the Exercise Price is received by the Company. The Warrant Shares
     shall be deemed to have been issued, and the Holder shall be deemed to have
     become a holder of record of such shares for all purposes, as of the date
     the Warrant has been exercised by payment to the Company of the Exercise
     Price and all taxes required to be paid by the Holder, if any, pursuant to
     Section 6 prior to the issuance of such shares, have been paid. If the
     Company fails to deliver to the Holder a certificate or certificates
     representing the Warrant Shares pursuant to this Section 4(a) by the third
     Trading Day following the Warrant Share Delivery Date, then the Holder will
     have the right to rescind such exercise. Nothing herein shall limit a
     Holder's right to pursue any remedies available to it hereunder, at law or
     in equity including, without limitation, a decree of specific performance
     and/or injunctive relief with respect to the Company's failure to timely
     deliver certificates representing shares of Common Stock upon exercise of
     the Warrant as required pursuant to the terms hereof.

               (b) If this Warrant shall have been exercised in part, the
     Company shall, at the time of delivery of the certificate or certificates
     representing Warrant Shares, deliver to Holder a new Warrant evidencing the
     rights of Holder to purchase the unpurchased Warrant Shares called for by
     this Warrant, which new Warrant shall in all other respects be identical
     with this Warrant.

               (c) The Company  shall not effect any  exercise of this  Warrant,
     and the Holder shall not have the right to exercise any portion of this
     Warrant, pursuant to Section 4(a) or otherwise, to the extent that after
     giving effect to such issuance after exercise, the Holder (together with
     the Holder's affiliates), as set forth on the applicable Notice of
     Exercise, would beneficially own in excess of 4.99% of the number of shares
     of the Common Stock outstanding immediately after giving effect to such
     issuance. For purposes of the foregoing sentence, the number of shares of
     Common Stock beneficially owned by the Holder and its affiliates shall
     include the number of shares of Common Stock issuable upon exercise of this
     Warrant with respect to which the determination of such sentence is being
     made, but shall exclude the number of shares of Common Stock which would be
     issuable upon (A) exercise of the remaining, nonexercised portion of this
     Warrant beneficially owned by the Holder or any of its affiliates and (B)
     exercise or conversion of the unexercised or nonconverted portion of any
     other securities of the Company (including, without limitation, any other
     Warrants) subject to a limitation on conversion or exercise analogous to
     the limitation contained herein beneficially owned by the Holder or any of
     its affiliates. Except as set forth in the preceding sentence, for purposes
     of this Section 4(c), beneficial ownership shall be calculated in
     accordance with Section 13(d) of the Exchange Act. To the extent that the
     limitation contained in this Section 4(c) applies, the determination of
     whether this Warrant is exercisable (in relation to other securities owned
     by the Holder) and of which a portion of this Warrant is exercisable shall
     be in the sole discretion of such Holder, and the submission of a Notice of
     Exercise shall be deemed to be such Holder's determination of whether this
     Warrant is exercisable (in relation to other securities owned by such
     Holder) and of which portion of this Warrant is exercisable, in each case
     subject to such aggregate percentage limitation, and the Company shall have
     no obligation to verify or confirm the accuracy of such determination. For
     purposes of this Section 4(c), in determining the number of

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     outstanding shares of Common Stock, the Holder may rely on the number of
     outstanding shares of Common Stock as reflected in (x) the Company's most
     recent Form 10-Q or Form 10-K, as the case may be, (y) a more recent public
     announcement by the Company or (z) any other notice by the Company or the
     Company's Transfer Agent setting forth the number of shares of Common Stock
     outstanding. Upon the written or oral request of the Holder, the Company
     shall within two Trading Days confirm orally and in writing to the Holder
     the number of shares of Common Stock then outstanding. In any case, the
     number of outstanding shares of Common Stock shall be determined after
     giving effect to the conversion or exercise of securities of the Company,
     including this Warrant, by the Holder or its affiliates since the date as
     of which such number of outstanding shares of Common Stock was reported.
     The provisions of this Section 4(c) may be waived by the Holder upon, at
     the election of the Holder, not less than 61 days' prior notice to the
     Company, and the provisions of this Section 4(c) shall continue to apply
     until such 61st day (or such later date, as determined by the Holder, as
     may be specified in such notice of waiver).

          5. No Fractional Shares or Scrip. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant. As to any fraction of a share which Holder would otherwise be entitled
to purchase upon such exercise, the Company shall pay a cash adjustment in
respect of such final fraction in an amount equal to such fraction multiplied by
the Exercise Price.

          6. Charges, Taxes and Expenses. All incidental expenses and taxes in
respect of the issuance of certificates for Warrant Shares shall be paid by the
Holder, and such certificates shall be issued in the name of the Holder.

          7. Closing of Books. The Company will not close its stockholder books
or records in any manner which prevents the timely exercise of this Warrant,
pursuant to the terms hereof.

          8. No Rights as Shareholder until Exercise. This Warrant does not
entitle the Holder to any voting rights or other rights as a shareholder of the
Company prior to the exercise hereof. Upon the surrender of this Warrant and the
payment of the aggregate Exercise Price, the Warrant Shares so purchased shall
be and be deemed to be issued to such Holder as the record owner of such shares
as of the close of business on the later of the date of such surrender or
payment.

          9. Loss, Theft, Destruction or Mutilation of Warrant. The Company
covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant or any stock
certificate relating to the Warrant Shares, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to it (which, in
the case of the Warrant, shall not include the posting of any bond), and upon
surrender and cancellation of such Warrant or stock certificate, if mutilated,
the Company will make and deliver a new Warrant or stock certificate of like
tenor and dated as of such cancellation, in lieu of such Warrant or stock
certificate.

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          10. Saturdays, Sundays, Holidays, etc. If the last or appointed day
for the taking of any action or the expiration of any right required or granted
herein shall be a Saturday, Sunday or a legal holiday, then such action may be
taken or such right may be exercised on the next succeeding day not a Saturday,
Sunday or legal holiday.

          11. Adjustments of Exercise Price and Number of Warrant Shares.

               (a) Stock  Splits,  etc. The number and kind of securities
     purchasable upon the exercise of this Warrant and the Exercise Price shall
     be subject to adjustment from time to time upon the happening of any of the
     following. In case the Company shall (i) pay a dividend in shares of Common
     Stock or make a distribution in shares of Common Stock to holders of its
     outstanding Common Stock, (ii) subdivide its outstanding shares of Common
     Stock into a greater number of shares, (iii) combine its outstanding shares
     of Common Stock into a smaller number of shares of Common Stock, or (iv)
     issue any shares of its capital stock in a reclassification of the Common
     Stock, then the number of Warrant Shares purchasable upon exercise of this
     Warrant immediately prior thereto shall be adjusted so that the Holder
     shall be entitled to receive the kind and number of Warrant Shares or other
     securities of the Company which it would have owned or have been entitled
     to receive had such Warrant been exercised in advance thereof. Upon each
     such adjustment of the kind and number of Warrant Shares or other
     securities of the Company which are purchasable hereunder, the Holder shall
     thereafter be entitled to purchase the number of Warrant Shares or other
     securities resulting from such adjustment at an Exercise Price per Warrant
     Share or other security obtained by multiplying the Exercise Price in
     effect immediately prior to such adjustment by the number of Warrant Shares
     purchasable pursuant hereto immediately prior to such adjustment and
     dividing by the number of Warrant Shares or other securities of the Company
     resulting from such adjustment. An adjustment made pursuant to this
     paragraph shall become effective immediately after the effective date of
     such event retroactive to the record date, if any, for such event.

               (b) Reorganization, Reclassification, Merger, Consolidation or
     Disposition of Assets. In case the Company shall reorganize its capital,
     reclassify its capital stock, consolidate or merge with or into another
     corporation (where the Company is not the surviving corporation or where
     there is a change in or distribution with respect to the Common Stock of
     the Company), or sell, transfer or otherwise dispose of its property,
     assets or business to another corporation and, pursuant to the terms of
     such reorganization, reclassification, merger, consolidation or disposition
     of assets, shares of common stock of the successor or acquiring
     corporation, or any cash, shares of stock or other securities or property
     of any nature whatsoever (including warrants or other subscription or
     purchase rights) in addition to or in lieu of common stock of the successor
     or acquiring corporation ("Other Property"), are to be received by or
     distributed to the holders of Common Stock of the Company, then the Holder
     shall have the right thereafter to receive, upon exercise of this Warrant,
     the number of shares of Common Stock of the successor or acquiring
     corporation or of the Company, if it is the surviving corporation, and
     Other Property receivable upon or as a result of such reorganization,
     reclassification, merger, consolidation or disposition of assets by a
     Holder of the number of shares of Common Stock for which this Warrant is
     exercisable immediately prior to such event. In

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     case of any such reorganization, reclassification, merger, consolidation or
     disposition of assets, the successor or acquiring corporation (if other
     than the Company) shall expressly assume the due and punctual observance
     and performance of each and every covenant and condition of this Warrant to
     be performed and observed by the Company and all the obligations and
     liabilities hereunder, subject to such modifications as may be deemed
     appropriate (as determined in good faith by resolution of the Board of
     Directors of the Company) in order to provide for adjustments of Warrant
     Shares for which this Warrant is exercisable which shall be as nearly
     equivalent as practicable to the adjustments provided for in this Section
     11. For purposes of this Section 11, "common stock of the successor or
     acquiring corporation" shall include stock of such corporation of any class
     which is not preferred as to dividends or assets over any other class of
     stock of such corporation and which is not subject to redemption and shall
     also include any evidences of indebtedness, shares of stock or other
     securities which are convertible into or exchangeable for any such stock,
     either immediately or upon the arrival of a specified date or the happening
     of a specified event and any warrants or other rights to subscribe for or
     purchase any such stock. The foregoing provisions of this Section 10 shall
     similarly apply to successive reorganizations, reclassifications, mergers,
     consolidations or disposition of assets.

          12. Voluntary Adjustment by the Company. The Company may at any time
during the term of this Warrant reduce the then current Exercise Price to any
amount and for any period of time deemed appropriate by the Board of Directors
of the Company.

          13. Notice of Adjustment. Whenever the number of Warrant Shares or
number or kind of securities or other property purchasable upon the exercise of
this Warrant or the Exercise Price is adjusted, as herein provided, the Company
shall give notice thereof to the Holder, which notice shall state the number of
Warrant Shares (and other securities or property) purchasable upon the exercise
of this Warrant and the Exercise Price of such Warrant Shares (and other
securities or property) after such adjustment, setting forth a brief statement
of the facts requiring such adjustment and setting forth the computation by
which such adjustment was made.

          14. Notice of Corporate Action. If at any time:

               (a) the Company shall take a record of the holders of its Common
     Stock for the purpose of entitling them to receive a dividend or other
     distribution, or any right to subscribe for or purchase any evidences of
     its indebtedness, any shares of stock of any class or any other securities
     or property, or to receive any other right, or

               (b) there shall be any capital reorganization of the Company, any
     reclassification or recapitalization of the capital stock of the Company or
     any consolidation or merger of the Company with, or any sale, transfer or
     other disposition of all or substantially all the property, assets or
     business of the Company to, another corporation or,

               (c) there shall be a voluntary or involuntary dissolution,
     liquidation or winding up of the Company;

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then, in any one or more of such cases, the Company shall give to Holder (i) at
least 20 days' prior written notice of the date on which a record date shall be
selected for such dividend, distribution or right or for determining rights to
vote in respect of any such reorganization, reclassification, merger,
consolidation, sale, transfer, disposition, liquidation or winding up, and (ii)
in the case of any such reorganization, reclassification, merger, consolidation,
sale, transfer, disposition, dissolution, liquidation or winding up, at least 20
days' prior written notice of the date when the same shall take place. Such
notice in accordance with the foregoing clause also shall specify (i) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, the date on which the holders of Common Stock shall be
entitled to any such dividend, distribution or right, and the amount and
character thereof, and (ii) the date on which any such reorganization,
reclassification, merger, consolidation, sale, transfer, disposition,
dissolution, liquidation or winding up is to take place and the time, if any
such time is to be fixed, as of which the holders of Common Stock shall be
entitled to exchange their Warrant Shares for securities or other property
deliverable upon such disposition, dissolution, liquidation or winding up. Each
such written notice shall be sufficiently given if addressed to the Holder at
the last address of Holder appearing on the books of the Company and delivered
in accordance with Section 16(d).

          15. Authorized Shares. The Company covenants that during the period
the Warrant is outstanding, it will reserve from its authorized and unissued
Common Stock a sufficient number of shares to provide for the issuance of the
Warrant Shares upon the exercise of any purchase rights under this Warrant. The
Company further covenants that its issuance of this Warrant shall constitute
full authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that such
Warrant Shares may be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of the Trading Market upon
which the Common Stock may be listed.

          Except and to the extent as waived or consented to by the Holder, the
Company shall not by any action, including, without limitation, amending its
certificate of incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms of this Warrant, but will at all times in good faith assist in the
carrying out of all such terms and in the taking of all such actions as may be
necessary or appropriate to protect the rights of Holder as set forth in this
Warrant against impairment. Without limiting the generality of the foregoing,
the Company will (a) not increase the par value of any Warrant Shares above the
amount payable therefor upon such exercise immediately prior to such increase in
par value, (b) take all such action as may be necessary or appropriate in order
that the Company may validly and legally issue fully paid and nonassessable
Warrant Shares upon the exercise of this Warrant, and (c) use commercially
reasonable efforts to obtain all such authorizations, exemptions or consents
from any public regulatory body having jurisdiction thereof as may be necessary
to enable the Company to perform its obligations under this Warrant.

          Before taking any action which would result in an adjustment in the
number of Warrant Shares for which this Warrant is exercisable or in the
Exercise Price, the

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Company shall obtain all such authorizations or exemptions thereof, or consents
thereto, as may be necessary from any public regulatory body or bodies having
jurisdiction thereof.

          16. Miscellaneous.

               (a) Jurisdiction. All questions concerning the construction,
     validity, enforcement and interpretation of the provisions of this Warrant
     shall be governed by and construed and enforced in accordance with the
     internal laws of the State of New York. Each party agrees that all legal
     proceedings concerning the interpretations, enforcement and defense of the
     transactions contemplated by this Warrant (whether brought against a party
     hereto or its respective affiliates, directors, officers, shareholders,
     employees or agents) shall be commenced exclusively in the state and
     federal courts sitting in the City of Rochester, New York. Each party
     hereto hereby irrevocably submits to the exclusive jurisdiction of the
     state and federal courts sitting in the City of Rochester, New York for the
     adjudication of any dispute hereunder or in connection herewith or with any
     transaction contemplated hereby or discussed herein, and hereby irrevocably
     waives, and agrees not to assert in any suit, action or proceeding, any
     claim that it is not personally subject to the jurisdiction of any such
     court, that such suit, action or proceeding is improper. Each party hereto
     hereby irrevocably waives personal service of process and consents to
     process being served in any such suit, action or proceeding by delivering a
     copy thereof via overnight delivery (with evidence of delivery) to such
     party at the address in effect for notices to it under this Warrant and
     agrees that such service shall constitute good and sufficient service of
     process and notice thereof. Nothing contained herein shall be deemed to
     limit in any way any right to serve process in any manner permitted by law.
     Each party hereto (including its affiliates, agents, officers, directors
     and employees) hereby irrevocably waives, to the fullest extent permitted
     by applicable law, any and all right to trial by jury in any legal
     proceeding arising out of or relating to this Warrant or the transactions
     contemplated hereby. If either party shall commence an action or proceeding
     to enforce any provision of the Warrant, then the prevailing party in such
     action or proceeding shall be reimbursed by the other party for its
     attorneys' fees and other costs and expenses incurred with the
     investigation, preparation and prosecution of such action or proceeding.

               (b) Restrictions. The Holder acknowledges that the Warrant Shares
     acquired upon the exercise of this Warrant, if not registered, will have
     restrictions upon resale imposed by state and federal securities laws.

               (c) Nonwaiver. No course of dealing or any delay or failure to
     exercise any right hereunder on the part of Holder shall operate as a
     waiver of such right or otherwise prejudice Holder's rights, powers or
     remedies, notwithstanding all rights hereunder terminate (i) on the
     Termination Date or (ii) upon cancellation of this Warrant in accordance
     with Section 3 hereof.

               (d) Notices. Any and all notices or other communications or
     deliveries required or permitted to be provided hereunder shall be in
     writing and shall be deemed given and effective on the earliest of (a) the
     date of transmission, if such notice or

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     communication is delivered via facsimile at the facsimile number set forth
     below prior to 5:00 p.m. (New York City time) on a Trading Day, (b) the
     next Trading Day after the date of transmission, if such notice or
     communication is delivered via facsimile at the facsimile number set forth
     below on a day that is not a Trading Day or later than 5:00 p.m. (New York
     City time) on any Trading Day, (c) the second Trading Day following the
     date of mailing, if sent by U.S. nationally recognized overnight courier
     service, or (d) upon actual receipt. For purposes of the applicable
     provisions of this Warrant, a "Trading Day" is a day on which the Company's
     Common Stock (a) is not suspended from trading on any Trading Market at the
     close of business and (b) has traded at least once on the Trading Market
     that is the primary market for the trading of the Company's Common Stock.

     All notices shall be confirmed to the parties hereto as follows:

     If to the Company:

     Mpower Holding Corporation
     175 Sully's Trail
     Pittsford, New York 14534
     Facsimile:  [   ]-[    ]
     Attention:  General Counsel

     If to the Holder:

     [        ]
     Facsimile:  [   ]-[    ]
     Attention:  [    ]

               (e) Limitation of Liability. No provision hereof, in the absence
     of any affirmative action by Holder to exercise this Warrant or purchase
     Warrant Shares, and no enumeration herein of the rights or privileges of
     Holder, shall give rise to any liability of Holder for the purchase price
     of any Common Stock or as a stockholder of the Company, whether such
     liability is asserted by the Company or by creditors of the Company.

               (f) Successors and Assigns. Subject to applicable securities
     laws, this Warrant and the rights and obligations evidenced hereby shall
     inure to the benefit of and be binding upon the successors of the Company
     and the successors and permitted assigns of Holder. The provisions of this
     Warrant are intended to be for the benefit of all Holders from time to time
     of this Warrant and shall be enforceable by any such Holder of Warrant
     Shares.

               (g) Amendment. This Warrant may be modified or amended or the
     provisions hereof waived with the written consent of the Company and the
     Holder.

               (h) Severability. Wherever possible, each provision of this
     Warrant shall be interpreted in such manner as to be effective and valid
     under applicable law, but if any provision of this Warrant shall be
     prohibited by or invalid under applicable law, such

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     provision shall be ineffective to the extent of such prohibition or
     invalidity, without invalidating the remainder of such provisions or the
     remaining provisions of this Warrant.

               (i) Headings. The headings used in this Warrant are for the
     convenience of reference only and shall not, for any purpose, be deemed a
     part of this Warrant.

                              ********************

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          IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
by its officer thereunto duly authorized.

Dated:  [        ]
                                  MPOWER HOLDING CORPORATION

                                  By:  ____________________________________
                                            Name:
                                            Title:

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                               NOTICE OF EXERCISE

To:      Mpower Holding Corporation

          (1) The undersigned has hereby been granted ________ Warrant
Shares of Mpower Holding Corporation pursuant to the terms of the attached
Warrant (only if exercised in full), and tenders herewith payment of the
exercise price in full, together with all applicable transfer and other taxes,
if any.

          (2) Payment shall take the form of lawful money of the United
States.

          (3) Please issue a certificate or certificates representing said
Warrant Shares in the name of the undersigned:

          ---------------------------------------

The Warrant Shares shall be delivered to the following:

          ---------------------------------------

          ---------------------------------------

          ---------------------------------------

                                                        [PURCHASER]

                                           By:
                                               ---------------------------------
                                           Name:
                                           Title:

                                           Dated:
                                                 -------------------------------<PAGE>

                                                                   EXHIBIT 10.21

                              CONSULTING AGREEMENT

         CONSULTING AGREEMENT, dated as of April 1,1998 the ("Effective Date")
entered into by and between Memory Pharmaceuticals Corp., a Delaware corporation
(the "Company"), and Eric R. Kandel, M.D., an Investigator of the Howard Hughes
Medical Institute (the "Institute") at the Institute's Laboratory at Columbia
University (the "University"), residing at 9 Sigma Place, Riverdale, New York,
10471 ("Consultant").

         WHEREAS, the Company is engaged in the research, development and
production of pharmaceutical products that improve memory or enhance cognition
for itself and for others with whom it now has or in the future will have
contractual relationships (the Company's "Field of Interest"); and

         WHEREAS, the Consultant has substantial experience in the Field of
Interest; and

         WHEREAS, the Company wishes to avail itself of the services of
Consultant to aid the business activities conducted by or on behalf of the
Company, and Consultant is willing to perform such services on the terms and
conditions set forth below.

         NOW, THEREFORE, the Company and Consultant, in consideration of the
mutual promises contained herein, hereby agree as follows:

         1.       Services

         1.1      The Company hereby retains as a consultant, and Consultant
hereby agrees to serve as a consultant to the Company, all on the terms and
conditions herein set forth.

         1.2      Consultant's services hereunder shall include (a) service as
Chairman of the Scientific Advisory Board of the Company, in which capacity the
Consultant shall consult on business or scientific matters with the Company's
Board of Directors, officers, employees and

<PAGE>

agents, at their request, as mutually agreed upon by the Company and the
Consultant, and (b) subject to the terms of this Agreement, including but not
limited to Section 1.3 below, such other services or special projects as shall
be mutually agreed upon by the Company and Consultant.

         1.3      The Company and Consultant agree that Consultant will be
engaged by the Company as a consultant for the exchange of ideas only and shall
not direct or conduct research for or on behalf of the Company.

         1.4      The Company and Consultant agree that Consultant will be an
independent contractor for all purposes including, but not limited to, payroll
and tax purposes, and that Consultant shall not in any way represent himself to
be an employee of the Company.

         1.5      Upon request by the Company, and at times mutually agreed upon
by the Company and Consultant, Consultant shall devote up to thirty (30) days
annually to providing consulting services to the Company pursuant to this
Agreement.

         1.6      Subject to the provisions of Sections 6 and 7, Consultant
agrees and acknowledges that, although the Company has retained his consulting
services on a part-time basis, during the term of his consultancy he will not
enter into any other agreement, arrangement, understanding or other relationship
pursuant to which he is obligated to render advice and services to any
commercial entity engaged in the Company's Field of Interest and that he will
limit the rendering of advice and services in the Company's Field of Interest to
the Company.

         1.7      Notwithstanding anything in this Agreement to the contrary,
the Company acknowledges that Consultant is an employee of the Institute and a
faculty member of the University and is subject to their respective policies,
including policies concerning consulting, conflicts of interest, and
intellectual property.

                                     - 2 -

<PAGE>

         2.       Term

         2.1      The period of Consultant's services under this Agreement will
be for an initial term beginning as of the Effective Date and ending on the
fourth anniversary of the Effective Date. Such period will automatically be
extended at the end of its term for an additional period of one (1) year, and
thereafter for successive additional periods of one (1) year, unless, at least
sixty (60) days prior to the end of such initial term or any such successive
term, either the Company or the Consultant elects to terminate this Agreement
effective as of the end of such term, in each case by written notice of
termination given by either party to the other at least sixty (60) days prior to
the commencement of such additional period. Notwithstanding the foregoing,
either party may terminate this Agreement by giving not less than six (6)
months' prior written notice to the other party. In addition, in the event that
Consultant is required to terminate this Agreement by the terms of his principal
employment or by law or by regulation of a competent governmental agency or
authority, Consultant may terminate this Agreement effective upon written notice
to the Company.

         2.2      Termination of this Agreement under Section 2.1 shall not
affect (a) the Company's obligation to pay for services previously performed by
Consultant or expenses reasonably incurred by Consultant for which Consultant is
entitled to reimbursement under Sections 3 and 4 herein, (b) the Company's
obligations to recognize the priority of the intellectual property rights of the
Institute or the University under Section 9, (c) the Company's obligations to
defend and indemnify the Consultant and the Institute under Section 16 below, or
(d) the Consultant's continuing obligations to the Company under Sections 6, 8.1
and 9, below.

                                     - 3 -
<PAGE>

         3.       Compensation

         (a)      As compensation for Consultant's services pursuant to this
Agreement, the Company has, as of the date hereof, permitted Consultant and
members of Consultant's immediate family to subscribe for the purchase of an
aggregate of five percent (5%) of the Company's outstanding Common Stock, $.001
par value (the "Common Stock"), at the initial subscription price of $.001 per
share, pursuant to the terms of various Subscription and Right of First Refusal
Agreements dated March 19, 1997 (the "Subscription Agreements"). As of the date
hereof, (i) there are no other shares of stock, stock options, rights or other
equity or equity-based securities, including shares of capital stock or debt
convertible into or exchangeable for shares of Common Stock (collectively,
"Securities"), issued or issuable by the Company to the Consultant (either
directly or indirectly) and (ii) such shares of Common Stock issued pursuant to
Subscription Agreements constitute (A) 5% of the Company's presently issued and
outstanding Common Stock and (B) 5% of the Company's Common Stock on a fully
diluted basis.

         (b)      As potential additional compensation for Consultant's services
pursuant to this Agreement, in the event that, at any time during the term of
this Agreement and until immediately prior to the closing of the Company's
initial public offering of Common Stock pursuant to a registration statement
filed with the United States Securities Exchange Commission (the "IPO"), the
Company issues additional shares of Common Stock or Common Stock Equivalents (as
defined below) in connection with a material equity financing (excluding shares
issued in the IPO) or a material strategic collaboration (a "Dilutive
Issuance"), the Company shall grant to Consultant an option to purchase an
aggregate number of additional shares of Common Stock such that, after giving
effect to such Dilutive Issuance by the Company and such grant to the
Consultant, the Consultant and members of Consultant's immediate family shall

                                     - 4 -

<PAGE>

continue to beneficially own, in the aggregate, the same percentage of the
Company's issued and outstanding Common Stock that they owned immediately prior
to such Dilutive Issuance (in each case determined pursuant to Section 3(e)).
Any such grant of an option to the Company shall be made pursuant to a stock
option agreement in form and substance satisfactory to the Company and
Consultant (a "Stock Option Agreement"), a copy of which shall also be furnished
by the Company to the Institute prior to its execution. For purposes of this
Agreement, "Common Stock Equivalents" shall mean any shares of capital stock of
the Company (other than the Common Stock) which, at the option of the holder
thereof, are immediately convertible into or exchangeable for shares of Common
Stock. Notwithstanding anything in this Agreement to the contrary, the
Consultant and the Company agree that the Company shall in no event grant the
Consultant options to purchase additional shares of Common Stock if, after
giving effect to such grant, the Consultant and members of Consultant's
immediate family would beneficially own, in the aggregate, more than five
percent (5%) of the Company's issued and outstanding Common Stock (as determined
pursuant to Section 3(e)). In addition, subject to the preceding sentence,
contemporaneously with and subject to the closing of the Company's IPO, the
Company shall grant to Consultant, pursuant to a Stock Option Agreement (a copy
of which shall also be furnished to the Institute), an option to purchase an
aggregate number of additional shares of Common Stock equal to the product of
(A) the number of options to purchase Common Stock outstanding immediately prior
to the closing of the Company's IPO (excluding options to purchase Common Stock
issued to the Consultant or to members of the Consultant's immediate family),
multiplied by (B) the percentage of the Company's issued and outstanding Common
Stock owned by the Consultant and members of Consultant's immediate family
immediately prior to the closing of the Company's IPO (determined pursuant to
Section 3(e)).

                                     - 5 -

<PAGE>

         (c)      For purposes of this Section 3, Securities issued or issuable
to the Consultant either directly or indirectly shall include, without
limitation, (i) any Securities issued or issuable by the Company to members of
the Consultant's immediate family and (ii) any Securities issued or issuable by
the Company to the Consultant, or Securities allocated or allocable to the
Consultant under the University's inventorship policies, as royalties under a
license by the Company of technology of which the Consultant is an inventor
("University Shares"), unless the Consultant has instructed the University not
to deliver or transfer University Shares to the Consultant personally but
instead to hold such shares until the University decides to liquidate them and
then to contribute the cash proceeds to the Consultant's laboratory.

         (d)      The Company acknowledges that it has been advised that the
Institute's policies prohibit the Consultant from holding, directly or
indirectly, more than five percent (5%) of any class of the Company's equity
securities, and that the Institute may have restricted the Consultant's ability
to exercise any stock option(s) granted to the Consultant by the Company, except
following an event of dilution. The Company agrees to disclose any such
restrictions in all materials describing the Consultant's holding in the
Company. In addition, the Company agrees that, if the Consultant has not already
done so, it will notify the Institute within sixty (60) days after each issuance
of Securities to the Consultant and each exercise by the Consultant of any stock
option(s), using a form of notice that provides the following information:

         -        description of each event that diluted the Consultant's
                  holdings (the "Dilutive Event"), including the total number
                  and class of additional shares of stock issued by the Company;

         -        summary of the Company's capitalization prior to the Dilutive
                  Event;

                                     - 6 -

<PAGE>

         -        summary of the Company's capitalization after the Dilative
                  Event;

         -        summary of the Consultant's equity holdings in the Company
                  prior to the Dilutive Event;

         -        date of exercise and description of equity issued to
                  Consultant as a result of such exercise; and

         -        summary of Consultant's equity holdings in the Company after
                  the exercise, including the percentage of the Company's
                  outstanding equity held by the Consultant.

         (e)      In determining the Consultant's percentage holdings of any
class of the Company's equity securities, the Company shall include in the
numerator all shares of such class the Consultant holds, directly or indirectly,
and all shares of stock of such class issuable to the Consultant, directly or
indirectly, upon the exercise of stock options, rights or other equity or
equity-based securities (other than shares issuable only upon the occurrence of
an event of dilution), but shall include in the denominator only shares of such
class actually issued and outstanding (except, in the case of shares of Common
Stock, the denominator shall also include all shares of Common Stock Equivalents
actually issued and outstanding), plus all shares of such class issuable to the
Consultant, directly or indirectly, upon the exercise of stock options, rights
or other equity or equity-based securities (other than shares issuable only upon
the occurrence of an event of dilution). Indirect holdings for purposes of this
Section 3(e) shall be determined as set forth in Section 3(c).

                                     - 7 -

<PAGE>

         (f)      The Company shall also pay the Consultant $30,000 per annum
during the term of this Agreement for the Consultant's service as Chairman of
the Scientific Advisory Board of the Company.

         4.       Expenses

         Consultant shall be entitled to reimbursement for reasonable travel and
other out-of-pocket expenses incurred in the performance of his duties hereunder
following submission of written statements and bills.

         5.       Absence of Restrictions

         Subject to Section 7 of this Agreement, Consultant represents and
warrants to the Company that he is under no contractual or other restriction or
obligation which is inconsistent with his execution of this Agreement or the
performance of his duties hereunder. During the term of this Agreement,
Consultant will not enter into any agreement either written or oral in conflict
with this Agreement and will arrange to provide his services under this
Agreement in such a manner and at such times that his services will not conflict
with his responsibilities under any other agreement, arrangement or
understanding or pursuant to any employment or consulting relationship
Consultant has at any time with any third party.

         6.       Competition with the Company

         Subject to Section 7 of this Agreement, at any time during the term of
this Agreement and for a period of two (2) years thereafter, the Consultant
shall not "compete" directly or indirectly with the Company. As used herein,
"compete" means to be involved for the account of one's self or another, as
owner, principal, stockholder, director, employee, officer, consultant, partner,
joint venturer, or in any other manner with any commercial business or entity
located in or doing

                                     - 8 -

<PAGE>

business located anywhere in the world in the Company's Field of Interest, or
which solicits any person employed by, or proposed for employment by, the
Company on the date of termination of Consultant's consultancy, or that employs
or solicits any person to terminate his or her employment by the Company. The
Consultant acknowledges that the Company is developing products and services to
be distributed throughout the world and that such non-competition provisions are
necessary to protect the Company's goodwill and business.

         7.       Other Obligations. The Company acknowledges and agrees that
nothing in this Agreement shall affect the Consultant's obligations to, or
research on behalf of, the Institute and the University, including, without
limitation, obligations or research of the Consultant in connection with a
transfer by the Institute or the University of materials or intellectual
property developed in whole or in part by Consultant, or in connection with
research collaborations.

         8.       Protected Information

         8.1      Consultant shall at all times, both during and after any
termination of this Agreement, maintain in confidence and shall not, without the
prior written consent of the Company, use, except in the course of performance
of Consultant's services for the Company, disclose or give to others any fact or
information which was disclosed to or developed by Consultant during the course
of performing services for the Company and identified as proprietary by the
Company (hereinafter, "Proprietary Information"). Except as provided in Section
8.2, Proprietary Information includes but is not limited to information and
facts concerning business plans, customers, future customers, suppliers,
licensors, licensees, partners, investors, affiliates or other, training methods
and materials, financial information, sales prospects, client lists, Company
Intellectual Property (as defined in Section 9 below) or any other scientific,
technical, trade or business secret or confidential or proprietary information
of the

                                     - 9 -

<PAGE>

Company or of any third party provided to Consultant in the course of
consultancy to the Company. Consultant also agrees not to file patents based on
the Company's Proprietary Information, nor seek to make improvements thereon,
without the Company's approval. Consultant agrees not to make any copies of such
Proprietary Information of the Company (except when appropriate for the
furtherance of the business of the Company or duly and specifically authorized
to do so) and promptly upon request, whether during or after the period of the
consulting arrangement, to return to the Company any and all documentary,
machine-readable or other elements or evidence of such Proprietary Information,
and any copies that may be in Consultant's possession or under Consultant's
control.

         8.2      Proprietary Information subject to Section 8.1 does not
include information that: (i) is or later becomes available to the public
through no breach of this Agreement by the Consultant; (ii) is obtained by the
Consultant from a third party who had the legal right to disclose the
information to the Consultant; (iii) is already in the possession of the
Consultant on the date this Agreement becomes effective; or (iv) is required to
be disclosed by law, government regulation, or court order. In addition,
Proprietary Information subject to Section 8.1 does not include information
generated by the Consultant unless the information (i) is generated as a direct
result of the performance of consulting services under this Agreement and (ii)
is not generated in the course of the Consultant's activities as an Institute
employee or University faculty member.

         8.3      Consultant may disclose to the Company any information that is
generally available to the public or that Consultant would normally freely
disclose to other members of the scientific community at large, whether by
publication, by presentation or seminars, or in informal scientific discussions
and, subject to the following sentence and to Section 9(c), the Consultant

                                     - 10 -

<PAGE>

agrees to notify the Company of any new developments in the Company's Field of
Interest made by the Consultant. However, the Consultant shall not disclose to
the Company information that is proprietary to the Institute and is not
generally available to the public other than through formal technology transfer
procedures.

         9.       Ownership of Ideas, Copyrights and Patents. (a) Subject to the
terms of Section 9(c), below, the Consultant hereby assigns to the Company any
right, title, and interest he may have in any idea, discovery, creation,
innovation, improvement, know-how, invention, design, development, apparatus,
technique, method or other intellectual property which (i) the Consultant
develops solely as a direct result of performing consulting services for the
Company under this Agreement and (ii) is not generated in the course of
Consultant's activities as an Institute employee or University faculty member
and is not owned by the Institute or assignable to the University. Any
intellectual property assignable to the Company pursuant to the preceding
sentence is hereinafter referred to as "Company Intellectual Property". Upon the
request of the Company, the Consultant shall execute such further assignments,
documents, and other instruments as may be necessary to assign Company
Intellectual Property to the Company and to assist the Company in applying for,
obtaining and enforcing patents or other rights in the United States and in any
foreign country with respect to any Company Intellectual Property. The Company
will bear the cost of preparation of all patent or other applications and
assignments, and the cost of obtaining and enforcing all patents and other
rights to Company Intellectual Property.

         (b)      Consultant agrees to maintain and furnish to the Company
complete and current records of all inventions that are Company Intellectual
Property and to disclose all Company Intellectual Property to the Company in
writing.

                                     - 11 -

<PAGE>

         (c)      Notwithstanding anything in this Agreement to the contrary,
the Company shall have no rights by reason of this Agreement in any publication,
invention, discovery, improvement, or other intellectual property whatsoever,
whether or not publishable, patentable or copyrightable, which is developed as
a result of a program of research financed, in whole or in part, by funds
provided by or under the control of the Institute or the University.
Notwithstanding anything in this Agreement to the contrary, the Company also
acknowledges and agrees that it will enjoy no priority or advantage as a result
of the consultancy created by this Agreement in gaining access to any
proprietary information or intellectual property that arises from any research
undertaken by Consultant in his capacity as an employee of the Institute or a
faculty member of the University.

         10.      Notices

         For purposes of this Agreement, notices and all other communications
provided for herein shall be in writing and shall be deemed to have been duly
given when delivered personally or by express courier with a receipt obtained
therefor or when mailed by United States registered or certified mail, return
receipt requested, postage prepaid, addressed as follows:

    If to Consultant, to:    Eric R. Kandel, M. D.
                             9 Sigma Place
                             Riverdale, New York 10471

    If to the Company, to:   Memory Pharmaceuticals Corp., c/o Oxford Ventures
                             45 Milk Street
                             Boston, MA 02109
                             Attn: Dr. Axel Unterbeck

    with a copy to:          Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
                             One Financial Center
                             Boston, MA 02111
                             Attn: Lewis J. Geffen

                                     - 12 -

<PAGE>

or to such other address as either party may furnish to the other in writing in
accordance with this section, except that notices of changes of address shall be
effective upon receipt.

         11.      No Waiver

         Waiver of any provision of this Agreement, in whole or in part, in any
one instance shall not constitute a waiver of any other provision in the same
instance, nor any waiver of the same provision in another instance, but each
provision shall continue in full force and effect with respect to any other
then-existing or subsequent breach.

         12.      Headings

         The paragraph headings have been inserted for purposes of convenience
only and shall not be used for interpretive purposes.

         13.      Assignment

         This Agreement, and the rights and obligations hereunder, may not be
assigned or transferred by either party without the prior written consent of the
other party, except the Company may assign this Agreement in connection with the
merger, consolidation, or sale of all or substantially all of the assets of the
Company. Subject to the foregoing, this Agreement shall be binding upon
Consultant and his heirs, executors, administrators, successors, representatives
and assigns and shall inure to the benefit of the Company and any successor or
assign of the Company.

         14.      Entire Agreement

         This Agreement, together with the Subscription Agreements and any Stock
Option Agreements, constitutes the entire agreement of the parties with regard
to the subject matter

                                     - 13 -

<PAGE>

hereof, and supersedes all previous written or oral representations, agreements,
and understandings between the Company and Consultant, whether expressed or
implied. This Agreement may be executed in one or more counterparts, each of
which shall be deemed to be an original, but all of which together will
constitute one and the same agreement. Any amendment or modification of this
Agreement or waiver of any right, in whole or in part, will be effective only if
it is in writing and signed by the parties hereto. The Company and Consultant
acknowledge that any amendment of this Agreement (including, without limitation,
any extension of this Agreement or any change from the terms of Section 3 and 4
in the consideration to be provided to Consultant with respect to services to be
provided hereunder) or any departure from the terms or conditions hereof with
respect to Consultant's consulting services for the Company is subject to the
Institute's prior written approval.

         15.      Applicable Law and Severability

         This Agreement shall be governed by the law of The Commonwealth of
Massachusetts. If a court of competent jurisdiction determines that any
provision of this Agreement is invalid or unenforceable, then the validity or
unenforceability of that provision shall not affect the validity or
enforceability of any other provision of this Agreement, and all other
provisions remain in full force and effect. If any of the provisions of this
Agreement is held to be excessively broad, it shall be reformed and construed by
limiting and reducing it so as to be enforceable to the maximum extent permitted
by law. Notwithstanding the foregoing, if any provision of this Agreement
affecting the rights or property of the Institute is adjudicated to be invalid,
unenforceable, contrary to, or prohibited under applicable laws or regulations
of any jurisdiction, this Agreement shall terminate as of the date such
adjudication is effective.

                                     - 14 -

<PAGE>

         16.      Defense and Indemnification.

         The Company agrees, at its sole expense, to defend the Consultant and
the Institute against, and to indemnify and hold the Consultant and Institute
harmless from, any claims or suits by a third party against the Consultant or
the Institute or any liabilities or judgments based thereon, either arising from
this Agreement, the Consultant's performance of services for the Company under
this Agreement, or any Company products which result from the Consultant's
performance of services under this Agreement.

         17.      Advertising.

         The Company will not use the Consultant's or the Institute's name in
any commercial advertisement or similar material that is used to promote or sell
products, unless the Company obtains in advance the written consent of the named
party to such use, and in the case of the use of the Consultant's name, the
Institute's consent as well; provided that the foregoing shall not cover
accurate, factual disclosure included in any financial disclosure or similar
document relating to the Company pursuant to the requirements of applicable
securities laws, rules and regulations.

                                     - 15 -

<PAGE>

         Consultant and the Company have executed and delivered this Agreement
as a document under seal as of the Effective Date.

                                                    MEMORY PHARMACEUTICALS CORP.

                                                    By: /s/ A. UNTERBECK
                                                       -------------------------
                                                    Name:  A. UNTERBECK
                                                    Title: President & CSO

                                                    CONSULTANT

                                                    /s/ ERIC R. KANDEL
                                                    ----------------------------
                                                    ERIC R. KANDEL, M.D.

                                     - 16 -

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