REPORT ON THE CRUSTACEA MACRURA. 



699 



The Challenger specimen was found at San Iago, Cape Verde Islands, and the type 

 in the British Museum, being that from which Mr. Newport's description was taken, was 

 obtained at San Nicolao, in the same group. 



Atya serrata, n. sp. (PL CXIX. fig. 2). 



Carapace less than one-third the length of the animal, anteriorly produced to a 

 rostrum that is about one-third the length of the carapace, slightly elevated to a central 

 carina on the upper surface, and produced on the under side to a ridge, the anterior 

 margin of which is serrate with three small teeth. 



The rest of the animal so closely corresponds with the specimens of Atya (Atyoida) 

 bisulcata, Randall, from Honolulu, that it is difficult to distinguish them by any other 

 feature. 



m. (1"4 in.). 



Habitat. — Valley of San Antonio, San Iago, Cape Verde Islands ; from a fresh-water 

 stream. 



This species, when placed side by side with the Honolulu specimens that I consider to 

 belong to Atya bisulcata (Randall), exhibits only slight and unimportant differences. 



The largest specimen from the Cape Verde Islands is nearly one-fourth longer than 

 the largest from Honolulu. The rostrum of the Cape Verde specimens is a little longer 

 in proportion than in those from Honolulu, it being three-tenths the length of the cara- 

 pace as compared with two-tenths in the Honolulu specimens. In Atya bisulcata the 

 dorsal median line of the rostrum is elevated as it is in Atya serrata, but the corre- 

 sponding median line on the under surface is smooth and receding, whereas in Atya 

 serrata it is deeper, laterally compressed, and furnished with three or four small, sharply 

 defined teeth ; this is the most distinguishing feature, and the one from which the species 

 takes its name. 



