HISTORY OF THE LOBSTER AND CRAB. 277 



launus. The resemblance between the young Cancer and Atelecyclus 

 led me to compare carefully the two forms, and I have come to the 

 conclusion that the Circular Crab has been erroneously classified. In 

 both Cancer and Atelecyclus there are lo teeth on the margin of 

 the carapace, in Corystes there are only four ; the two former also 

 agree in the form of the external manillipeds, in the shortness of the 

 antennae, in the short and robust character of the pincher-claws or 

 chelipeds, and in the form and teeth of the rostrum, in all of which 

 points they differ from Corystes. 



Atelecyclus, then, must be in future be considered as a member 

 of the family Cancridae, and it is an interesting fact that the young 

 Cancer, immediately after its metamorphosis, has the pointed teeth 

 of Atelecyclus, which it also resembles somewhat in the form of the 

 carapace. Afterwards changes occur, which produce the condition 

 of the adult Cancer. The young of the edible crab has not hitherto 

 been described, at least these peculiarities in it have never been 

 before described, although, as already mentioned, they have been 

 noted in the newly-developed young of the American form Cancer 

 irroratus. I hope to publish a fuller description of these specimens, 

 with figures, in the Proceedings of the Zoological Society of 

 London. 



