DECAPODA. 209 



or boggy soil; others resort to the rocky flats or 

 beaches to bask in the sun, where only an occasional 

 wave dashes over them, and seek refuge in the sea 

 when alarmed; while some species are completely 

 terrestrial, inhabiting holes upon the highest hills 

 and mountains of the West Indies. 



The Spider Crabs (Oxyrynchus}* have their shells of a triangular 

 shape, narrowed in front into a point which almost resembles a beak. 

 The legs are long and very slender, this necessarily leads to slowness 

 of motion ; but they are well fitted to a residence amongst rocks and 

 stones covered with seaweed, among which they stride with little 

 difficulty. In the winter they become almost, if not altogether, 

 torpid, concealing themselves at this season either in deep crevices 

 of rocks or imbedded in the soil. These long-legged crabs are fre- 

 quently covered with seaweeds, sponges, and other marine pro- 

 ductions, which so completely change their appearance, that they are 

 no longer recognizable. Mr. Gosse observed at Ilfracombe the 

 exuviation of a large Spider Crab which had retired into a crevice. 

 When securing it he felt the body fall away from the carapa.ce, and 

 on looking at the crab, found the new carapace perfectly formed and 

 coloured beneath it. The limbs and the under parts still remained 

 invested with their old shell. In a short time the hind legs were 

 freed, and then the animal extricated the front pair, tugging first at 

 one and then at the other as if drawing off a pair of boots. The 

 par^s had a jelly-like softness, and seemed to be compressed as they 

 were liberated by the fluids being forced back so as to distend the 

 freed portion of the limb. Mr. Gosse did not observe any struggling 

 it seemed a very simple and easy matter. The new integuments 

 were complete, though soft, before the old were torn off; and the 

 immediate cause of the separation of the crust appeared to be the 

 sudden growth of the animal within forcing asunder the upper and 

 lower shells at the posterior margin. 



The Swimming Crabs (Pinnipedes)^ have the hinder feet termi- 

 nated by a flat joint resembling a fin. They live at a distance from 

 the shore, and swim out into the high sea. 



The Shore Crabs (Cancer} are eminently adapted for walking. 

 The eight hinder legs only are employed for the purpose, and they 



FlG. 159. YOUNG OF CRAB. 



* ovs, oxys, sharp ; ftfoxos, rhyncos, a snout 

 t Pinna, a feather or leaflet ; pes, pedis, a foot. 



