Exhibit 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our reports dated May 24, 1999, included in this Form 8-K/A, into the Company's previously filed Registration Statements File No.'s 333-83587, 333-79197, 333-51711 and 333-35791. /s/ ARTHUR ANDERSEN LLP ARTHUR ANDERSEN LLP Boston, Massachusetts July 23, 1999