From The Collaborative International Dictionary of English v.0.48 [gcide]:
Hamadryas \Ha*ma"dry*as\ (h[.a]*m[=a]"dr[i^]*[a^]s), n. [L., a
hamadryad. See Hamadryad.] (Zool.)
The sacred baboon of Egypt (Cynocephalus Hamadryas).
[1913 Webster]