CRUSTACEANS. 491 



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. Pennant's well- 

 known sympathy 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 the 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 pieces, but 

 the vestiges of the separation of the 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 projecting 

 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 from the 

 points of the antennae. Tracing this to its origin, it became evident 

 that it was produced by the rapid vibration of the foot-jaws drawing 

 in the surrounding water, and pouring it off upwards between the 

 united antennas, as through a tube. Then, on examining these organs, 

 I perceived that the form and arrangement of their bristles did indeed 



