oxyrhynch - I could not find dictionary definition, and found only a site mentioning it. The roots suggest it means “pointed nose”

I think that it is because this is a proper noun, perhaps the genus of the crab?

MALACOSTRACA. Under this zoological title are included
several groups of Crustacea (qv), united by characters which attest their common origin, though some, and probably all of them, were already separated in distant geological ages, and some have now attained a peculiar isolation.
There are at least seven orders: the stalk-eyed Brachyura, Macrura, Schizopoda, Stomatopoda, and the sessile-eyed Sympoda, Isopoda, Amphipoda.
1. BRAcnyuitA.—For the present, as of old, the true Brachyura are divided into four tribes: Cyclometopa, with arched front as in the common eatable crab; Catometopa, with front bent down as in the land-crabs and the little oyster-crab; Oxyrhyncha, with sharpened beak-like front as in the various spider-crabs; Oxystomala, including the Raninidle, and named not from the character of the front but from that of the buccal frame which is usually narrowed forwards.

In the family Homolidae stands the strange genus Latreillia, Roux, with long slender limbs and triangular carapace after the fashion of oxyrhynch spider-crabs.