S. I. Smith on American Cuustacea. 141 



little contracted behind, and, in general form, a short cylinder trun- 

 cated at each end. The chelipeds and ambulatory legs are slender 

 and elongated. 



The dorsal surface of the carapax is naked, smooth and shining, 

 convex longitudinally, deeply areolated and nearly symmetrical. The 

 cervical sutiire is slightly curved and very distinctly marked by a 

 deep sulcus. The median portion of the gastric region is triangular, 

 and is separated from the antero-lateral lobes by very distinct but 

 shallow sulci, which meet in an acute angle on tlie front. The cardiac 

 region is large, quite prominent and distinctly separated from the 

 gastric. The branchial regions are very prominent and swollen, pro- 

 jecting much above the median regions, and a narrow portion next 

 the cervical suture is cut oft* by a straight and sharp sulcus. The 

 front projects well forward and is quite narrow, but not contracted 

 between the bases of the ocular peduncles. The superior border of 

 the orbit is nearly on a plain with the anterior part of the carapax, 

 its anterior edge is strongly arcuate and is marked by a very slight, 

 but sharply raised and continuous margin, and the posterior edge is 

 marked by a faintly raised line, which is transverse and nearly 

 straight toward the front, but, toward the side of the carapax, falls 

 off posteriorly, so that the antero-lateral angle, which is right-angular, 

 but not at all prominent, is considerably posterior to the rest of the 

 anterior margin. The faintly margined lateral borders are parallel 

 anteriorly but approach slightly posteriorly. The inferior border of 

 the orbit is denticulate, the teeth being very minute on the portion 

 toward the front but much larger, and very slender on the outer 

 portion, and round into the external hiatus. The jugal regions are 

 much swollen and are separated from the buccal area by a deep 

 depression. 



The ocular peduncles are quite stout and as long as the orbits, 

 which they nearly fill. 



The ischial segments of the external maxillipeds are very broad 

 and the outer edges are arcuate to fit the expanded buccal area, and 

 thus resemble the species of section A. 



The larger cheliped is remarkably developed for so small a species, 

 the merus being as long as the carapax, while the hand is almost three 

 times as long, and nearly twice as long as the breadth of the cai-apax. 

 The anterior surface of the merus is smooth, flat and quite narrow, 

 and its angles are smooth and unarmed. The superior and exterior 

 surface of the carpus is evenly rounded and very slightly granulous, 

 and the inner margin is sharp and dentate. The basal portion of the 



