133 



and I, therefore, do not believe their smrtU size and pecnliar form to be 

 due to age ; their presence is rather a sexual characteristic. 



The inferior distal angle of the propodos of the third and fourth pairs 

 of thoracic feet is produced, and when the joint is flexed this projection 

 impinges against the antero-inferior angle of the carpus. This char- 

 acter is not mentioned in Dana's description. In other respects they 

 are almost identical. 



Length, .10 to .15 of an inch. 



PLATYSCELID^. 



PLATYSCELUS BATE!, u. sp. 



Head, when viewed from above, broadly rounded ; the center of the 

 anterior margin produced in the form of a beak, which is directed down 

 ward. The peduncle of the superior antennae truncated ; the inferior 

 distal extremity furnished with two bunches of auditory cilia, one pos- 

 terior to the other 5 flagellum two-jointed. Inferior antenute short, four- 

 jointed; first joint the longest; second and third subequal ; fourth joint 

 broadly rounded at apex, longer than the third ; terminating in a minute 

 flagellum, acute and curved at the apex, and base broader. The whole 

 antenna is concealed beneath the lateral portion of the bead. The 

 thorax narrower at either extremity than in the middle, somewhat barrel- 

 shaped when seen from above: first and second segment short, almost con- 

 cealed in the middle of the dorsum by the overriding of the third. The 

 first pair of gnathopoda shorter and slightly stouter than the second ; in 

 other respects they are similar ; shorter and more robust than the follow- 

 ing thoracic feet ; neither carpi nor mera produced anteriorly, the latter 

 broader than the former, neither serrated ; the inferior margins furnished 

 with a few long setse; propoda about the same length as the carpi, nar- 

 rower, cylindrical, not serrated; dactyla short. The first pair of thoracic 

 feet shorter than the second ; coxse of both pairs elongate, somewhat 

 clavate; the mera, carpi, and propoda subequally long; dactyla short, 

 curved. Coxa of third pair subelliptical, not serrated ; apex obtusely 

 rounded ; anterior margin furnished with five or six short, equidistant 

 setse; the remaining five joints articulating with coxa subapically, 

 together as long as the coxa ; at the inferior apex of the third joint is a 

 single long seta. Coxa of the fourth pair broad, arcuate posteriorly, 

 and excavate anteriorly; distal extremity obtusely rounded at the ayex, 



