EXHIBIT 4.25

                                  WAM!NET INC.

                            A MINNESOTA CORPORATION


No. 1                                                5,710,425 Shares of Class B
                                                     Convertible Preferred Stock

 
          This certifies that Silicon Graphics, Inc. is the registered holder of
                              ----------------------                            
Five Million Seven Hundred Ten Thousand Four Hundred Twenty-five Shares of Class
B Convertible Preferred Stock, par value $0.01 per share (see reverse side),
transferable only on the books of the Corporation by the holder hereof in person
or by Attorney upon surrender of this Certificate properly endorsed.

          IN WITNESS WHEREOF, the said Corporation has caused this Certificate
to be signed by its duly authorized officers this 4th day of March, 1999.

 

                         /s/ Edward J. Driscoll III
                         -------------------------------------------
                         Edward J. Driscoll III, President

 

                         /s/ Edward J. Driscoll, Jr.
                         -------------------------------------------
                         Edward J. Driscoll, Jr. Secretary

 
          The Class B Convertible Preferred Stock has the rights and preferences
as set forth in the Certificate of Designation of Class B Preferred Stock as
filed of record with the Minnesota Secretary of State on March 4, 1999.

          The securities evidenced hereby are subject to the terms of that
certain Stockholders Agreement, dated as of March 4, 1999, by and among the
Corporation, Silicon Graphics, Inc. and MCI WORLDCOM, Inc., including certain
restrictions on transfer.  A copy of this Agreement has been filed with the
Secretary of the Corporation and is available upon request.  The securities
evidenced hereby have not been registered under the Securities Act of 1933, as
amended (the "Act") and may not be resold, transferred or otherwise disposed of
other than in a transaction exempt from, or not subject to, the registration
requirements of the Act or pursuant to an effective registration statement
thereunder.

          For value received, __________ does hereby sell, assign and transfer
unto ____________ Shares represented by the within Certificate and does hereby
irrevocably constitute and appoint ________ Attorney to transfer the said Shares
on the books of the within named Corporation with full power of substitution in
the premises.

Dated:_____________________


                                         _______________________________________

NOTE:  The signature on this assignment must correspond with the name as written
upon the face of the Certificate, in every particular, without alteration or
enlargement or any change whatever.

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