'652 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



carina extending two-thirds of the lengtli, but not well marked upon 

 the fifth. 



The telson is pretty regularly triangular, about twice as long as broad, 

 is convex and slightly grooved longitudinally above, and terminates in 

 an acutely rounded tiji unarmed with spines. The lamelUe of the uro- 

 pods scarcely reach the tip of the telson ; the outer is nearly as broad 

 as long, regularly rounded in outline, and stiffened by two shghtly di- 

 verging ribs in addition to the thickening of the outer margin ; the in- 

 ner lamella is stiffened by a single median rib, is nearly twice as long as 

 broad, tbe lateral margins are approximately straight and parallel, and 

 the tip is regularly rounded in outline. 



The first pair of pleopods are about 15""" long with an imperfect arti- 

 culation at about a third of the way from the base to the tip ; the basal 

 portion is somewhat triquetral, and the terminal portion expands into a 

 smooth, naked, and thin lanceolate lamella slightly concave posteriorly. 

 The second pair of pleopods are about 24'"'" long, and the base and 

 lamellfc are of about equal lengths. The lamellae are narrow, lanceo- 

 late, and thickly ciliated along the edges ; the inner lamella is slightly 

 broader than the outer, and bears the two styliform processes usually 

 chara(5teristic of males among the Macrura. These styliform processes 

 are about 3""" long, and arise together at about a third of the way from 

 the base to the tip of the lamella ; the inner, like that upon the three 

 succeeding pairs of pleopods, arises from the slightly thickened inner 

 edge of the lamella, is ridged, of nearly equal width to the rounded tip, 

 and nearly naked except a line of cilia along the posterior margin. The 

 outer process arises just in front of the inner, and its base is at a right 

 angle to that of the outer ; it is more slender than the outer, tapers dis- 

 tally, and is ciliated on both edges and on the anterior surface. The 

 three succeeding pairs of pleopods are similar to those of the second 

 pair, but are successively a little shorter, and they want the outer of the 

 two styliform processes on the inner margin of inner lamella. 



The single specimen examined affords the following measurements: 



mm. 



Length IVoui fiout of carapax to tip of telsou 92 



Lengtli of carapax along median line 39 



Length of carapax between extremities of lateral margin 45 



Breadth between lateral spines of anterior margin 20 



Breadth between postero-lateral angles (abont) 22 



Greatest breadth (in front of cervical sntirre) 30 



Length of first perteopod to near distal end of merus 40 



Length of second perteopod 33 



Length of fifth, or last, perieopod 20 



Length of peduncle of antennula 9 



Length of major fiagellum 45 



Length of minor flagellnm 13 



Length of peduncle of antenna 12 



Length of antennal scale 9 



Length of fiagellum (at least) 30 



Length of pleon 53 



Length of telson > 16 



