64 On a new Macrurous Crustacean. 



the tergal and pleural regions are most sharply defined as such, 

 the former not curving continuously with the latter, but termi- 

 nating abruptly at the level of the ventral chords in a line 

 convex outwards ; so that if a somite were detached, deprived 

 of its ventral chord, and flattened out on the table with its dorsal 

 surface uppermost, the imaginary continuation from pleuron 

 to pleuron of the plane in which these pleura lay would pass 

 below that of the surface of the tergum. 



The " swimmeret" constituted as in all other Macrurous 

 Crustacea by the highly modified and backwardly placed ap- 

 pendages of the last postabdominal somite and by the " telson" 

 differs in no particular of more than specific value from that of 

 Nephrons • the mesial element, or telson, is longer in propor- 

 tion to its breadth, its greatest breadth being a transverse line 

 separating its anterior from its middle third, and not at the 

 base as in Nephrops, is slightly more truncate posteriorly ; 

 and the oblique rounded elevations, that gradually narrow 

 as they pass backwards into the spines at its postero-lateral 

 angles, are stronger than in Nepthrops. The outer plate of 

 the lateral elements of the swimmeret is movably articu- 

 lated at its posterior third, as in the rest of the Astacidce ; but 

 the sutural line is curved, and the posterior margin of the prox- 

 imal and larger division exhibits hardly a trace of the over- 

 lapping denticulation seen in other Astacidce. 



millim. 

 Length from tip of rostrum to the posterior margin of telson . . 98 



Length of carapace in middle line 42 



Length of postabdomcn 56 



therefore the postabdomen : carapace (rostrum inch) : : 1| : 1 exactly, 

 and the length of body : that of postabdomen : : 1| : 1 „ 



The only specimen (a female) obtained was dredged in from 

 260 to 300 fathoms, about 25 miles off Ross Island, on the 

 eastern coast of the Andamans. That the specimen was really 

 brought up from this great depth is certain from the unmis- 

 takable signs of crushing from contact with the lip of the 

 dredge, from its position in the dredge-bag, and from its firmly 

 adherent greenish coating, which appears to indicate that, like 

 Calocaris Macandrece, it was a burrower. 



In conclusion, I have to thank Captain Beresford, the com- 

 mander of the vessel, for his skilful management of the sound- 

 ing-line and for the zeal displayed by him in carrying out my 

 wishes during our too short cruise. 



I have much pleasure in connecting with this extremely 

 interesting species the name of Major-General Donald M. 

 Stewart, C.R., Chief Commissioner of the Andaman and 

 Nicobar Islands, to whose ever ready help the success of my 

 trip was so largely due. 



