Exhibit 23.1


                                CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


     As independent public  accountants,  we hereby consent to the incorporation
of our report  included in this Form 10-K, into the Company's  previously  filed
Registration  Statement File No. 33-83494 on Form S-1; Nos. 33-95702,  33-97542,
333-02892,  333-20245 and 333-24493 on Form S-8; and Nos.  33-99220,  333-09401,
333-  13733  and  333-18159  on Form S-3.  It  should be noted  that we have not
audited any financial statements of the Company subsequent to December 31, 1997,
or performed any audit procedures subsequent to the date of our report.



                                                          ARTHUR ANDERSEN LLP



Dallas, Texas
January 29, 1998