424 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



wiiicli is armed with a minute spiue, projecting forward just inside of tlie 

 peduncle of the antenna ; between these spines the edge of the front is 

 uptunuMl in a sharp marginal carina, which terminates each side in the 

 spines themselves. The dorsal surface of this pcirt of the carapax is 

 convex in both directions, the protogastric lobes are protuberant and 

 well marked, and nearly the whole surface is roughened, and more or 

 less tubercuiose, with transverse scabrous elevations, which give rise to 

 numerous hairs. The branchial regions are slightly swollen, so that the 

 breadth of the carapax posteriorly is greater than in front. All the por- 

 tions back of the cervical suture are smooth and membrana(;eous. 



The eye-stalks are about half as long as the carapax in front of the 

 cervical suture, liatrened and expanded distally, where they are about 

 three-fourths as broad as long. The eye itself is black, and the cornea 

 extends round either side so as to be crescent-shaped as seen from above. 

 The ophthalmic scales are less than half as long as the ej'e-stalks, nar- 

 row, triangular, and acute. 



The first ami second segments of the peduncle of the antennula are 

 subequal in length, and the ultimate segment nearly once and a half as 

 long as the penultimate, and almost as long as the eye-stalks. Tlie 

 superior, or major, flagellum is nearly as long as the ultimate segment 

 of the i)eduncle ; the thick, ciliated basal portion consists of about four- 

 teen segments, and the slender terminal portion, which is nearly once 

 and a half as long as the basal, of about fiv^e very slender and subequal 

 segments. The minor flagellum is about two-thirds as long as the major, 

 and comjjosed of about eight segments. The peduncle of the antenn^i 

 reaches by the eye nearly the length of the last segment, which is about 

 as long as the greatest diameter of the eye. The acicle is slender, acute, 

 and slightly longer than the last segment of the peduncle. The flagel- 

 lum reaches beyond the tips of the ambulatory legs. 



The chelipeds are slender and very nearly equal in length, but the 

 right is very much stouter than the left. In the right cheliped the 

 merus and carpus are subequal in length, together nearly twice as long 

 as the carai^ax, and both are rough and obscurely spinous, the spines 

 being most conspicucms on the edges of the ui)per surface of the carpus, 

 which is fully three times as long as broad, flattened above, and angular, 

 but not distinctly carinated along either side. The chela is not far 

 from twice as long as the carpus, nearly three times as long as broad, 

 compressed vertically, evenly rounded, smooth and nearly naked above, 

 but clothed with long, soft hair beneath ; the digits are longitudinal, 

 not gaping, and the dactylus is about two-thirds as long as the basal 

 portion of the propodus, and its prehensile edge is armed with a broad 

 tooth near the middle. In the left cheliped the merus and carpus are 

 simdar to those of the right, but much more slender and a little longer; 

 the carpus is about six times as long as broad, and the edges of the 

 npper surface are rather more sharjAy angular than in the right ; tlie 

 chela is shorter than the right, but very slender, smooth, and nearly 



