1. relating to or possessing a testa or hard shell; - Example: "testaceous fish"
The Collaborative International Dictionary of English v.0.48:
Testaceous \Tes*ta"ceous\, a. [L. testaceus, fr. testa a shell.
1. Of or pertaining to shells; consisted of a hard shell, or
having a hard shell.
2. (Bot. & Zool.) Having a dull red brick color or a brownish
Testaceous animals (Zool.), animals having a firm,
calcareous shell, as oysters and clams, thus distinguished
from crustaceous animals, whose shells are more thin and
soft, and consist of several joints, or articulations, as
lobsters and crabs.
WordNet (r) 3.0 (2006):
adj 1: relating to or possessing a testa or hard shell;