66 
HISTORY OF BRITISH CRUSTACEA. 
Gen. 22. CORYSTES, Latr. 
Carapace much longer than wide, with a few teeth ; front 
lamellar, forming a triangular beak. Outer antennae very 
large, much longer than carapace, and furnished on upper 
and lower margins with a row of long hairs. Eore legs of 
male very long. 
Mr. Couch thus refers to the use of the long antennae. 
He says that our species burrows in the sand, leaving only 
the ends of its antennae projecting above the surface ; he 
supposes that these organs are of some use beyond their 
common office of feelers, perhaps assisting in the process of 
excavation. He remarks, cc 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 antennae 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"* 
Corystes Cassivelaunus, Penn. sp. Pennant’s Long- 
armed Crab . (Plate IY. fig. 5.) — Carapace swollen, with two 
irregular waving grooves, which to the fanciful eye seem to 
* Cornish Fauna, p. 74. 
