Webster's Revised Unabridged Dictionary · 1913

Testaceous

Testaceous , adjective

[Latin testaceus, from testa a shell. See Testa.]

1.
Of or pertaining to shells; consisted of a hard shell, or having a hard shell.
2.
(Botany & Zoology) Having a dull red brick color or a brownish yellow color.
Collocations (1)
Testaceous animals (Zoology) , 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.