202 Bulletin Vanderbilt Marine Museum, Vol. V 



which is lightly carinate. The carapace has its dorsal surface moder- 

 ately convex in both directions, tumid, the urogastric and cervical 

 grooves deep and on either side of it two transverse depressions, the 

 anterior of which is short and oblique ; the second, longer one extends 

 obliquely outward toward the lateral margin ; the region between these 

 sulci is quite tumid and emphasized on its outer portion by a concen- 

 tration of large granules. The circumscribed gastric region is polished, 

 smooth, except for a few small granules sparsely scattered toward the 

 outer margins ; the cardiac and intestinal regions are similarly nearly 

 smooth; the outer postlateral margin and the branchial and hepatic 

 regions are very nearly covered with coarse tubercles, these concen- 

 trating to form two clusters on the outer branchial region, beyond 

 which the branchial area slopes abruptly to the margin. The side- 

 walls and more conspicuously the pterygostomian region are covered 

 with rounded coarse granules. The excurrent channel is very sharply 

 defined. The epistome is short, wide, sinuate, with carinate margins. 

 The sternal plastron is smooth, except for microscopic granules. It is 

 composed of five fused plates, corresponding to the five legs. The 

 male belt is triangulate, seven-segmented, the first and especially the 

 second article, being quite short, the seventh a blunt triangle. The 

 female belt is widely oval, covering the entire sternal plastron; it is 

 composed of seven segments. The eggs are quite minute ; the female 

 here illustrated has several thousand. 



The external maxillipeds are close-fitting, nearly twice as wide as 

 long, subrectangular. The exognath is linear, rodlike, its inner mar- 

 gin fitting beneath the endognath. The ischium of the endognath has 

 its greatest width equal to the length of its straight outer lateral mar- 

 gin ; the basal margin is very oblique, tapering inward ; the inner lat- 

 eral margin retreats obliquely toward the meral joint. The distal 

 ischial margin is slightly oblique, the outer angle obtuse. The merus 

 is bent upward and is wider than long, with its inner margin rounded 

 and bordered by a wide, flat carina ; the distal margin is concave and 

 narrow and the outer lateral margin is convex, widening toward its 

 proximal angle. The three-jointed palp has its basal article produced 

 into a thickened, rimlike, outer lateral margin, the upper side of which 

 fits closely under the epistome ; the lower portion of the article is lami- 

 nate, with the rounded lateral margin fitting beneath the merus ; the 

 second article is nearly as wide as long, rather fleshy ; the third article 

 is short, thick, conical; the lower lateral and outer distal margin of 

 the peduncle is heavily fringed with thick-set setae ; the outer lateral 

 and distal margins of the other two segments are also heavily fringed. 



