ALLORCHESTES. 
39 
The inferior antennae have the basal articulation not 
so closely fused with the head as in Orchestia, and a 
small olfactory denticle is visible. The foot-jaws ter- 
minate in a sharp curved nail. The hands of the first 
two pairs of legs are subchelate in both sexes. The an- 
terior pair are small, the second are generally large and 
powerful in the male. In the female, though occasion- 
ally smaller than those of the male, they are never rudi- 
mentary, and are generally developed upon the type of 
the male, except that the wrist is produced along the 
inferior margin of the hand. The first joint (or coxa) of 
the first four pairs of limbs is large and squamiform, being 
nearly as deep as the body of the animal. The first joint 
of the fifth pair of legs is much shorter than that of the 
preceding pairs. The caudal appendages are short and 
stout, the posterior being unibranched. 
In habits as well as in organization, Allorchestes occu- 
pies a position between Orchestia and Gammarus. It is a 
littoral genus, dwelling generally under weed upon the 
shore, and in pools left by the sea. One species only, 
A. medius , is recorded by Dana as having been taken by 
the dredge in two separate localities, in several fathoms 
of water. 
The geographical range of this genus is very wide. 
It is found throughout the temperate and subarctic 
zones of both hemispheres. 
Under the name of Enone Risso has described (Eu- 
rope meridionale, p. 96) a genus which we believe to be 
identical with the present; but the description is so des- 
titute of distinctive characters, that it is not sufficient 
to warrant its acceptance even as a synonym. 
