The Collaborative International Dictionary of English v.0.48:

Hystricomorphous \Hys`tri*co*mor"phous\
   (h[i^]s`tr[i^]*k[-o]*m[^o]r"f[u^]s), a. [Hystrix + Gr. morfh`
   form.] (Zool.)
   Like, or allied to, the porcupines; -- said of a group
   (Hystricomorpha) of rodents.
   [1913 Webster]