SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13D
                                 (Rule 13d-101)

             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
            TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO
                                  RULE 13d-2(a)

                              (Amendment No. 3)(1)

                          Catalyst Semiconductor, Inc.
                                (Name of Issuer)

                                  Common Stock
                         (Title of Class of Securities)

                                   148881-10-5
                                 (CUSIP Number)

                              Attn: Paul B. Goucher
                       J. & W. Seligman & Co. Incorporated
                                 100 Park Avenue
                               New York, NY 10017
                                 (212) 850-1864
                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)

                                January 28, 2008
             (Date of Event Which Requires Filing of This Statement)

If the filing person has previously  filed a statement on Schedule 13G to report
the  acquisition  that is the subject of this  Schedule  13D, and is filing this
schedule  because of Rule  13d-1(e),  13d-1(f) or 13d-1(g),  check the following
box. |_|

Note:  Schedules  filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
to whom copies are to be sent.

                         (Continued on following pages)

(1) 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 disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purposes of Section 18 of the  Securities  Exchange Act of
1934 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).



CUSIP No. 148881-10-5                  13D/A

--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     J. & W. Seligman & Co. Incorporated
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |_|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     AF
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    0
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        1,996,866
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           0
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    1,996,866
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,996,866
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     11.8%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     IA, CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       2


CUSIP No. 148881-10-5                  13D/A

--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     Seligman Spectrum Focus (Master) Fund
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |_|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     WC
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Cayman Islands
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    0
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        1,884,066
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           0
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    1,884,066
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,884,066
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     11.2%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       3


CUSIP No. 148881-10-5                  13D/A

--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     William C. Morris
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |_|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     AF
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     USA
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    0
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        1,996,866
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           0
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    1,996,866
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,996,866
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     11.8%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     IN
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       4


                                  SCHEDULE 13D

This  amendment is being filed to replace and supersede the entire  Schedule 13G
filed in error on January 28, 2008 by the  Reporting  Persons  named  herein and
Seligman  Communications  and Information Fund, Inc. The Reporting Persons named
herein  continue to be persons  required to file a Schedule  13D and  amendments
thereto with respect to the common stock of Catalyst Semiconductor, Inc.

Item 1. Security and Issuer.

The name of the issuer is Catalyst  Semiconductor,  Inc., a Delaware corporation
(the "Issuer").  The address of the Issuer's principal  executive office is 2975
Stender Way,  Santa Clara,  CA 94054.  This  Amendment No. 3 to the Statement on
Schedule 13D relating to the Issuer's  common  stock,  no par value (the "Common
Stock"),  is being  filed  jointly  by J. & W.  Seligman & Co.  Incorporated,  a
Delaware  corporation  ("JWS"),  Seligman Spectrum Focus (Master) Fund, a Cayman
Islands corporation ("SSF"), and William C. Morris,  controlling  shareholder of
JWS ("Morris"  and,  together with JWS and SSF, the  "Reporting  Persons"),  and
supplements  and amends the Statement on Schedule 13D originally  filed with the
Commission on June 25, 2007 and amended on August 24, 2007 and January 11, 2008.

Item 3. Source and Amount of Funds or Other Consideration.

In  acquiring  the Common  Stock  reported  in Item 5(c)  herein,  SSF  expended
approximately  $1.66 million (including  commissions) of its working capital and
another client for whom JWS acts as an investment adviser expended approximately
$27,700 (including commissions) of its working capital.

Item 5. Interest in Securities of the Issuer.

(a), (b) Based on the Issuer's  Report on Form 10-Q filed with the Commission on
December  12,  2007,  there were  16,879,645  shares of Common  Stock issued and
outstanding as of November 30, 2007. As to each Reporting Person, Items (7)-(11)
and (13) of their respective cover page are incorporated herein by reference.

JWS and Morris do not directly  own any shares of the Issuer.  The shares of the
Issuer  reported  herein are directly  owned by SSF and one other client of JWS;
SSF and such other client have each engaged JWS as their investment adviser with
discretionary  authority to acquire,  dispose and vote the shares of the Issuer.
JWS, as investment  adviser to SSF and such other client,  and Morris,  as JWS's
controlling  shareholder,  may be  deemed  to have the  shared  power to vote or
direct  the vote of (and the shared  power to dispose or direct the  disposition
of) the Common Stock reported herein.

(c) The trading  dates,  number of shares of Common Stock  purchased or sold and
the price per share for all transactions by the Reporting  Persons in the Common
Stock within the last 60 days,  which were all executed by  broker-dealers,  are
set forth below:



------------------------------------------------------------------------------------------------------------
     Reporting Person              Date            # of shares Purchased / (Sold)      Price Per Share
------------------------------------------------------------------------------------------------------------
                                                                                    
           SSF                   1/18/2008                     22,500                       3.5755
------------------------------------------------------------------------------------------------------------
           SSF                   1/9/2008                     100,000                        3.75
------------------------------------------------------------------------------------------------------------
           SSF                  12/20/2007                     80,000                        4.00
------------------------------------------------------------------------------------------------------------
           SSF                  12/20/2007                     20,000                       4.1451
------------------------------------------------------------------------------------------------------------
           SSF                  12/17/2007                    163,100                        4.56
------------------------------------------------------------------------------------------------------------
           SSF                   12/4/2007                     9,500                         5.00
------------------------------------------------------------------------------------------------------------
     JWS f/b/o client           12/17/2007                     5,500                         4.56
------------------------------------------------------------------------------------------------------------
     JWS f/b/o client            12/4/2007                      500                          5.00
------------------------------------------------------------------------------------------------------------



                                       5


(d) No person other than the  Reporting  Persons has the right to receive or the
power to direct the receipt of dividends  from, or the proceeds from the sale of
the Common Stock reported herein; provided,  however, that one JWS client (not a
Reporting Person  hereunder) owning 112,800 shares of Common Stock of the Issuer
has the right to receive any  dividends  paid by the Issuer and could  terminate
its investment  advisory  relationship with JWS and then subsequently direct the
use of proceeds from the sale of the Common Stock owned by such client.

                                    SIGNATURE

            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: January 28, 2008

                                   J. & W. SELIGMAN & CO. INCORPORATED


                                   By: /s/ Thomas G. Rose
                                       -----------------------------------------
                                       Name: Thomas G. Rose
                                       Title: CFO

                                   SELIGMAN SPECTRUM FOCUS (MASTER) FUND


                                   By: /s/ Lawrence P. Vogel
                                       -----------------------------------------
                                       Name: Lawrence P. Vogel
                                       Title: Authorized Person

                                   WILLIAM C. MORRIS
                                       By Frank J. Nasta,
                                       as attorney-in-fact for William C. Morris


                                   /s/ Frank J. Nasta
                                   --------------------------------------------


                                       6