188 LIFE BY THE SEASHORE. 



seeing a specimen for the first time, and noting the length 

 of leg, the triangular carapace, and the dense coating of 

 spines, is likely at once to pronounce it to be a spiny spider- 

 crab. Not infrequently he writes to the newspapers to 

 proclaim the fact; the spiny spider-crab as an inhabitant 

 of the North-east may indeed be relied upon to appear as 

 regularly as the nightingale, the humming-bird, the sea- 

 serpent, and the other phenomena of the dead season. 



If you are fortunate enough to obtain a specimen, you 

 may easily enough demonstrate to yourself the reasons why 

 Lithodes is not a spider-crab, but is relegated to a family of 

 its own, the Lithodidae, which is placed at a considerable 

 distance from the true crabs. 



The stone-crab has a triangular spiny carapace prolonged 

 into a long rostrum, which bears eight spines. There are 

 no orbits, or eye-sockets, and the eyes are placed at the 

 inner side of the antennae (contrast crabs). The antennules 

 lie beneath the eyes, and have a very long stalk, and very 

 short flagella (cf. hermit-crabs). The antenna? are long, and 

 placed not in a complete socket, but in a gap between a 

 spine on the carapace and one on the anterior end of the 

 gill-cover (cf. Porcellana, and contrast crabs). The gill- 

 cover itself is nearly vertical (cf. Pagurus and Galathea), 

 and divided into several pieces. As in Pagurus, the last 

 ring of the thorax is movable, and is not covered by the 

 carapace, and its appendages are greatly reduced, and 

 concealed in life beneath the carapace. As in Pagurus and 

 Galathea, the third maxillipede is completely leg-like, and 

 does not form an operculum, as in the true crabs. The first 

 pair of legs only are truly chelate, the others are very long. 

 Both carapace and legs are spiny, and are of the same dull 

 red colour. 



So far Lithodes has only been seen to resemble Pagurus 

 in those points in which Pagurus itself resembles Galathea, 

 or even more distant forms, but in the structure of the 

 abdomen, Lithodes, on the other hand, shows a striking 

 affinity to Pagurus, and to Pagurus alone. In Lithodes, as 

 in Pagurus, the abdomen is incompletely calcified, the first 

 two segments are large and visible on the dorsal surface, the 

 remaining segments are permanently flexed beneath the 

 thorax. In the female these segments are markedly un- 



