2244 CRUSTACEA. 



Front obtuse. Cephalothorax five- or six-jointed, the head separate, 

 only three posterior segments, the fourth obsolete, posterior angles 

 transversely truncate and exteriorly very short acute. Superior eyes 

 usually separate, the inferior of moderate size. Anterior antennse 

 twenty-two- to twenty-four-jointed, a little shorter than the body, 

 very widely divaricate, the tips curving a little forward; setse short, 

 straight, posterior penult longer than apical or other subapical, the 

 apical not longer than the joint, the anterior subapical very short. 

 Right antenna of male incrassate at middle, subterete, twelve- to 

 thirteen-jointed, third joint elongate, obsoletely jointed, seventh 

 (eighth?) short and subtriangular, next two slender and long. 

 Right leg of posterior pair of male very stout cheliform, hand sub- 

 ovate, immoveable finger lateral, obtuse, moveable finger elongate, 

 twice longer, slender and curved. Caudal stylets short, five sub- 

 equal setae. 



Plate 80, fig. la, male, enlarged; a', part of right male antenna; b, 

 profile of head ; c, maxillipeds (magnified twice as much as fig. 7 a); 

 d, anterior feet; e, posterior thoracic feet, in male; /, same, in female; 

 g, under view, showing the organs of the head and mouth; h, i, diffe- 

 rent views of a distorted female abdomen. 



Collected several specimens in the Pacific, two hundred and fifty 

 miles southwest of Tongatabu, latitude 26° 8' south, longitude 178° 

 west, April 18, 1840; also, March 25, 1841, south of the Kingsmill 

 Islands, latitude 5° 20' south, longitude 175° 30' east; and afterwards, 

 north of the equator in this group, near Hall's Island. 



Length, one-twelfth to one-sixteenth of an inch. Colour, bluish. 

 The truncate posterior extremity of the cephalothorax, with the outer 

 angles still acute, afford a striking character. In the antennae and the 

 eyes, this species is much like the preceding. The anterior antennae 

 curve forward and outward from the head, and the two afterwards 

 are very nearly in the same straight line. The maxillipeds are much 

 larger than the following pair of organs. The last five joints of the 

 anterior antennae are subequal and short. The setae towards the base 

 of the antenna are rather crowded, and longer than the diameter of 

 the organ. 



The right antenna of the male has the third joint rather longer 



