74 
GENUS ATELECYCLUS: Carapace large, arched anteri- 
orly, more contracted behind. Cavities of the antennas 
longitudinal, the front denticulated. 
BIDENTICULATED CRAB. A. Heterodon. M. Edwards’ 
Crust., vol. 2, p. 143. 
Common in the stomachs of fishes, chiefly Cod fishes and 
Rays, from the depth of 20 to 50 fathoms. They must abound 
at these depths, as I have found more than thirty in a single 
fish, and almost every Ray opened for several days in succes- 
sion was found to contain them. 
GENUS CORYSTES : Carapace much larger than wide, 
and in shape approaching to an ellipse. Outer Antennae 
very long, and inserted in a cavity of the orbitary foramen. 
LONG CRAB. C. Denlalus. M. Edwards’ Crust , vol. 2, p. 
148. C. Cassivalaunus, Leach’s Malac., pi. 1. Cancer, C. 
Pennant, pi. 7. C. Personatus of some writers. 
It is scarcely common, which may be accounted for from its 
habit of burrowing in the sand, leaving the extremities of its 
antennae alone projecting above the surface. These organs 
are of some use beyond their common office of feelers; per- 
haps as in some other Crustaceans, they assist in the process 
of excavation; and when soiled by labour I have seen the Crab 
effect their cleaning by alternately bending the joints of their 
stalks, which stand conveniently angular for this purpose. 
Each of the long antenna; is thus drawn along the brush that 
fringes the internal face of the other, until both are cleared of 
every particle that adhered to them. 
FAMILY of ANOMOURS. 
PTERYGURES, a subfamily having a pair of moveable ap- 
pendages at the extremity of the abdomen. 
PAGURIANS, or HERMIT CRABS. 
GENUS PAGURUS: the abdomen large and membranous, 
turned sideways; the pairs of abdominal feet irregular. 
HERMIT CRAB. P. Bernardus. M. Edwards’ Crust., vol. 
2, p. 215. P. Streblonyx, Leach’s Malac., pi. 26. Pennant, 
pi. 17. 
Common and abundant, the smaller in pools left by the tide, 
the larger in a considerable depth of water; where they be- 
come so large as to occupy Whelk shells (Buccinum) of the 
largest size : for as Crabs of this genus are weak and de- 
fenceless on the hinder parts of their body, they exercise the 
well known habit of residing in the empty shells of various 
species of the turbinated family ; moving about in this cover- 
ing, from the earliest ascertained stage of their existence, as if 
the structure were a portion of their own bodies. They 
