SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G
                                 (Rule 13d-102)

 INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c),
         AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b)
                               (Amendment No. 1)*







                         Magellan Health Services, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)



                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)



                                    559079207
--------------------------------------------------------------------------------
                                 (CUSIP Number)



                                December 31, 2004
--------------------------------------------------------------------------------
             (Date of Event which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

              [_] Rule 13d-1(b)

              [X] Rule 13d-1(c)

              [_] Rule 13d-1(d)



* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                                     Page 1





CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          Tudor Investment Corporation
         -----------------------------------------------------------------------
          22-2514825
         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  Delaware
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power               0
                                         ---------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       119,078
Owned by Each                              -------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power          0
                                               ---------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  119,078
                                                --------------------------------
--------------------------------------------------------------------------------
     9) Aggregate Amount Beneficially Owned by Each Reporting Person
                                                 119,078
                              --------------------------------------------------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.4%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  CO
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 2




CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          Paul Tudor Jones, II
         -----------------------------------------------------------------------

         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  USA
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power               0
                                         ---------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       128,000
Owned by Each                              -------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power          0
                                              ----------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  128,000
                                                --------------------------------
--------------------------------------------------------------------------------
     9)  Aggregate Amount Beneficially Owned by Each Reporting Person
                                                 128,000
                              --------------------------------------------------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.5%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  IN
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 3




CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          Tudor Proprietary Trading, L.L.C.
         -----------------------------------------------------------------------
          13-3720063
         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  Delaware
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power             0
                                          --------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       8,922
Owned by Each                              ------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power        0
                                              ----------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  8,922
                                                --------------------------------
--------------------------------------------------------------------------------
     9) Aggregate Amount Beneficially Owned by Each Reporting Person  8,922
                                                                     -----------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.0%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  OO
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 4




CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          The Tudor BVI Global Portfolio Ltd.
         -----------------------------------------------------------------------
          98-0223576
         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  Cayman Islands
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power              0
                                         ---------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       16,569
Owned by Each                              -------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power         0
                                              ----------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  16,569
                                                --------------------------------
--------------------------------------------------------------------------------
     9) Aggregate Amount Beneficially Owned by Each Reporting Person  16,569
                                                                     -----------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.1%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  CO
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 5




CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          The Altar Rock Fund L.P.
         -----------------------------------------------------------------------
          06-1558414
         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  Delaware
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power         0
                                         ---------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       0
Owned by Each                              -------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power    0
                                              ----------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  0
                                                --------------------------------
--------------------------------------------------------------------------------
     9) Aggregate Amount Beneficially Owned by Each Reporting Person  0
                                                                     -----------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.0%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  PN
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 6




CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          The Raptor Global Portfolio Ltd.
         -----------------------------------------------------------------------
          98-0211544
         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  Cayman Islands
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power         0
                                         ---------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       0
Owned by Each                              -------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power    0
                                              ----------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  0
                                                --------------------------------
--------------------------------------------------------------------------------
     9) Aggregate Amount Beneficially Owned by Each Reporting Person  0
                                                                     -----------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.0%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  CO
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 7



CUSIP No. 559079207
          ---------
--------------------------------------------------------------------------------
    1) Names of Reporting Person

       S.S. or I.R.S. Identification No. of Above Person

          Witches Rock Portfolio Ltd.
         -----------------------------------------------------------------------
          98-0439973
         -----------------------------------------------------------------------
--------------------------------------------------------------------------------
    2) Check the Appropriate Box if a Member of a Group (See Instructions)

       (a)
           ---------------------------------------------------------------------
       (b)  X
           ---------------------------------------------------------------------
--------------------------------------------------------------------------------
    3) SEC Use Only
                    ------------------------------------------------------------
--------------------------------------------------------------------------------
    4) Citizenship or Place of Organization  Cayman Islands
                                            ------------------------------------
--------------------------------------------------------------------------------
                   (5) Sole Voting Power               0
                                         ---------------------------------------
Number of Shares   -------------------------------------------------------------
Beneficially       (6) Shared Voting Power       102,509
Owned by Each                              -------------------------------------
Reporting Person   -------------------------------------------------------------
With               (7) Sole Dispositive Power          0
                                              ----------------------------------
                   -------------------------------------------------------------
                   (8) Shared Dispositive Power  102,509
                                                --------------------------------
--------------------------------------------------------------------------------
     9) Aggregate Amount Beneficially Owned by Each Reporting Person  102,509
                                                                     -----------
--------------------------------------------------------------------------------
    10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares
        (See Instructions)
                           -----------------------------------------------------
--------------------------------------------------------------------------------
    11) Percent of Class Represented by Amount in Row 9  0.4%
                                                        ------------------------
--------------------------------------------------------------------------------
    12) Type of Reporting Person (See Instructions)  CO
                                                    ----------------------------
--------------------------------------------------------------------------------


                                     Page 8




Item 1(a).    Name of Issuer:

              Magellan Health Services, Inc

Item 1(b).    Address of Issuer's Principal Executive Offices:

              6950 Columbia Gateway Drive
              Suite 400
              Columbia, Maryland 21046

Item 2(a).    Name of Person Filing:

              Tudor Investment Corporation ("TIC")
              Paul Tudor Jones, II
              Tudor Proprietary Trading, L.L.C. ("TPT")
              The Tudor BVI Global Portfolio Ltd. ("BVI Portfolio")
              The Altar Rock Fund L.P. ("Altar Rock")
              The Raptor Global Portfolio Ltd. ("Raptor Portfolio")
              Witches Rock Portfolio Ltd. ("Witches Portfolio")

Item 2(b).    Address of Principal Business Office or, if none, Residence:

              The principal business office of each of TIC, Altar Rock, and TPT
              is:

                   1275 King Street
                   Greenwich, CT 06831

              The principal business office of Mr. Jones is:

                   c/o Tudor Investment Corporation
                   1275 King Street
                   Greenwich, CT 06831

              The principal business office of each of BVI Portfolio, Raptor
              Portfolio, and Witches Portfolio is:

                   c/o CITCO
                   Kaya Flamboyan 9
                   Curacao, Netherlands Antilles

Item 2(c).    Citizenship:

              TIC is a Delaware corporation.
              Mr. Jones is a citizen of the United States.
              TPT is a Delaware limited liability company.
              Altar Rock is a Delaware limited partnership.
              Raptor Portfolio, Witches Portfolio and BVI Portfolio are
                 companies organized under the laws of the Cayman Islands.

Item 2(d).    Title of Class of Securities:

              Common Stock

Item 2(e).    CUSIP Number:

              559079207


                                     Page 9




Item 3.  If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b),
         check whether the person filing is a:
         (a) [ ] Broker or Dealer registered under section 15 of the Act
         (b) [ ] Bank as defined in section 3(a)(6) of the Act
         (c) [ ] Insurance Company as defined in section 3(a)(19) of the Act
         (d) [ ] Investment Company registered under section 8 of the Investment
                 Company Act
         (e) [ ] Investment Adviser registered under section 203 of the
                 Investment Advisers Act of 1940
         (f) [ ] Employment Benefit Plan, Pension Fund which is subject to the
                 provisions of the Employee Retirement Income Security Act of
                 1974 or Endowment Fund; see section 240.13d-1(b)(1)(ii)(F)
         (g) [ ] Parent Holding Company, in accordance with section
                 240.13d-1(b)(1)(ii)(G) (Note: See Item 7)
         (h) [ ] Group, in accordance with section 240.13d-1(b)(1)(ii)(H)

Item 4.  Ownership (As of December 31, 2004).

         (a) Amount Beneficially Owned: See Item 9 of cover pages

         (b) Percent of Class: See Item 11 of cover pages

         (c) Number of shares as to which such person has:

             (i)  sole power to vote or to direct the vote

                  See Item 5 of cover pages
                  -------------------------

             (ii) shared power to vote or to direct the vote

                  See Item 6 of cover pages
                  -------------------------

             (iii) sole power to dispose or to direct the disposition of

                   See Item 7 of cover pages
                   -------------------------

             (iv) shared power to dispose or to direct the disposition of

                  See Item 8 of cover pages
                  -------------------------

              The shares of Common Stock reported herein as beneficially owned
         are owned directly by TPT (8,922 shares), Witches Portfolio (102,509
         shares), and BVI Portfolio (16,569 shares). Because TIC provides
         investment advisory services to Witches Portfolio and BVI Portfolio,
         TIC may be deemed to beneficially own the shares of Common Stock owned
         by each of such Reporting Persons. TIC expressly disclaims such
         beneficial ownership. In addition, because Mr. Jones is the controlling
         shareholder of TIC and the indirect controlling equity holder of TPT,
         Mr. Jones may be deemed to beneficially own the shares of Common Stock
         deemed beneficially owned by TIC and TPT. Mr. Jones expressly disclaims
         such beneficial ownership.


Item 5.  Ownership of Five Percent or Less of a Class.

              If this statement is being filed to report that as of the date
         hereof the reporting person has ceased to be the beneficial owner of
         more than five percent of the class of securities, check the following
         [X].


Item 6.  Ownership of More than Five Percent on Behalf of Another Person.

              Not applicable

Item 7.  Identification and Classification of the Subsidiary Which Acquired the
         Security Being Reported on By the Parent Holding Company.

              Not applicable

Item 8.  Identification and Classification of Members of the Group.

              See cover pages

Item 9.  Notice of Dissolution of Group.

              Not applicable


                                     Page 10






Item 10. Certification.

         By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


                         Dated: February 14, 2005


                         TUDOR INVESTMENT CORPORATION


                         By:  /s/ Stephen N. Waldman
                             ---------------------------------------------------
                             Stephen N. Waldman
                             Managing Director and Associate General Counsel




                          /s/ Paul Tudor Jones, II
                         -------------------------------------------------------
                          Paul Tudor Jones, II

                         TUDOR PROPRIETARY TRADING, L.L.C.


                         By:  /s/ Stephen N. Waldman
                             ---------------------------------------------------
                             Stephen N. Waldman
                             Managing Director and Associate General Counsel

                         THE TUDOR BVI GLOBAL PORTFOLIO LTD.

                         By: Tudor Investment Corporation,
                             Trading Advisor

                             By:  /s/ Stephen N. Waldman
                                 -----------------------------------------------
                                 Stephen N. Waldman
                                 Managing Director and Associate General
                                   Counsel

                         THE ALTAR ROCK FUND L.P.

                         By: Tudor Investment Corporation,
                             General Partner


                             By:  /s/ Stephen N. Waldman
                                 -----------------------------------------------
                                 Stephen N. Waldman
                                 Managing Director and Associate General
                                   Counsel


                                     Page 11




                         THE RAPTOR GLOBAL PORTFOLIO LTD.

                         By: Tudor Investment Corporation,
                             Investment Adviser


                             By:  /s/ Stephen N. Waldman
                                 -----------------------------------------------
                                 Stephen N. Waldman
                                 Managing Director and Associate General Counsel


                         WITCHES ROCK PORTFOLIO LTD.

                         By: Tudor Investment Corporation,
                             Investment Advisor


                             By:  /s/ Stephen N. Waldman
                                 -----------------------------------------------
                                 Stephen N. Waldman
                                 Managing Director and Associate General
                                   Counsel


                                     Page 12