The Collaborative International Dictionary of English v.0.48:

Collagenous \Col*lag"e*nous\, a. (Physiol.)
   Containing or resembling collagen.
   [1913 Webster]

WordNet (r) 3.0 (2006):

collagenous
    adj 1: relating to or consisting of collagen [syn:
           collagenous, collagenic]