5l6 THE OCEAN WORLD. 



elongated claw, which is straight-pointed and channeled longitudi- 

 nally : the carapace oblong-oval, terminating in a rostrum anteriorly 

 truncated and bordered posteriorly; the regions are but slightly 

 indicated, with the exception of the caudal region, the branchial or 

 thoracic regions being very much elongated. 



Latreille gives the name of Corystes which signifies a warrior 

 armed to this genus of short-tailed Decapod Crustacean, from /cJpus, 

 a helmet. Pennant had already conferred the name of Cassivelaunus, 

 the chief of the ancient Britons, for the singular reason, according 

 to Gosse, that the carapace, which is marked by wrinkles, bears, in 

 old males especially, the strongest and most ludicrous resemblance 

 to the face of an ancient man, but surely Pennant's well-known sym- 

 pathy with his British ancestry certainly never led him to caricature the 

 grand old British warrior, as Mr. Gosse surmises. On the contrary, 

 he saw in this Crustacean a creature armed at all points, and he 

 named it after the hero of his imagination. 



In this species the surface of the carapace is somewhat granulous, 

 .with two denticles between the eyes, and three sharp points directed 

 forward on each side. The male has only five abdominal segments, 

 but the vestiges of the separation of two others may be clearly re- 

 marked upon the outer mediate or third piece, which is the largest of 

 all. The length of the antennae is remarked on by Mr. Couch, in 

 his " Cornish Fauna." " These organs," he says, " are of some use 

 beyond their common office of feelers ; perhaps, 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 alter- 

 nately bending the joints of their stalks, which stand conveniently 

 angular for the 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." On the other 

 hand, Mr. Gosse suggests that the office of the antennae is to keep a 

 passage open for ejecting the deteriorated water after it has bathed 

 and aerated the gills. "I have observed/' he says, "that, when kept 

 in an aquarium, these crabs are fond of sitting bolt upright, the 

 antennae placed close together, and pointing straight upwards from 

 the head. This is doubtless the attitude in which the animal sits in 

 its burrow, for the tips of the antennae may often be seen just project- 

 ing from the sand. When the chosen seat has happened to be so 

 close to the glass side of the tank as to bring the antennae within the 

 range of a pocket lens, I have minutely investigated these organs 

 without disturbing the old warrior in his meditation. I saw on each 

 occasion that a strong current of water was continuously pouring up 



