The Collaborative International Dictionary of English v.0.48:

Saxicavous \Sax`i*ca"vous\, a. [L. saxum rock + cavare to make
   hollow, fr. cavus hollow: cf. F. saxicave.] (Zool.)
   Boring, or hollowing out, rocks; -- said of certain mollusks
   which live in holes which they burrow in rocks. See Illust.
   of Lithodomus.
   [1913 Webster]