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                                                                    EXHIBIT 23.1
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
     As independent public accountants, we hereby consent to the incorporation
of our report dated February 3, 1999 included in this Annual Report on Form
10-K, into the Company's previously filed registration statements on Form S-3
(File No. 333-69693) and on Form S-8 (File No. 333-42165 and File No.
333-70043).
 
                                        ARTHUR ANDERSEN LLP
 
Houston, Texas
March 30, 1999