MUSEUM OF COMPARATIVE ZOOLOGY. 135 



but almost obsolete anteriorly. Margins of carapax crenulated, the teeth 

 being most distinct on the flattened, expanded, and broadly rounded lateral 

 angle, where they are about six in number, not crenulated, and but little 

 projecting, being denned chiefly by the impressed lines on the marginal 



limb. On the hepatic region there are two or three denticulated teeth. 

 Posterolateral margin slightly concave. Posterior margin convex; its 

 lateral angles obtuse. Rostrum rather prominent and faintly tridentate at 

 the extremity ; median tooth smallest and most prominent. External 

 angle of orbit not prominent. Eye large, with a very minute tubercle at 

 the summit. In the external antennae the basal joint is about equal to 

 the next in length. Subhepatic region less eoncave than in >'. typicus, 

 and without any supplementary ridge. External maxillipeds and afferent 

 channels nearly as in S. typicus, but with the ridges less strongly tubercu- 

 lated, and with the outer angle of the meros-joint less acutely prominent. 

 Sternum between the bases of the chelipeds convex on either side, but 

 not tuKerculated. Chelipeds very long and slender; edges denticulated. 

 hut with the surface between them smooth and polished: meros with 

 about thirteen denticles on either edge, the third denticle from the outer 

 extremity being larger than the others; hand with twelve sharp, forward- 

 curving teeth on the superior edge, the terminal tooth above the finger 

 being spiniform and considerably longer than the others; outer edge of 

 hand with about eleven obtuse, equal, less prominent, minutely crenulated 

 teeth; inner edge with nineteen or twenty very minute teeth Ambula- 

 tory feet naked and compressed, but without laminiform crests; meros- 

 joint of the posterior pair slightly expanded below near the base. In the 

 male the sternum and abdomen are smooth and glabrous; abdomen broad 

 at the base and narrower at the third joint. 



Dimensions of a male ; Length of the carapax, 0.25 ; breadth, 0.27 inch; 

 proportion, 1:1.08; length of meros-joint of cheliped, 0.29; length of 

 hand, 0.32 inch. 



Off Carysfort Reef, March 21, 1869. Cast No. 8. 35 fathoms 



Off Carysfort Reef, March 21, 1869. Cast No. 7. 40 



Off Conch Reef, March 21, 1869. fast No. I. 40 



Off French Reef, March 21, 1869. Ca-t No. 2. 45 



Off Carysfort Reef, March 21, 1869. Cast No. 6. 48 



Off Conch Reef, May 11, 1869. Cast No. 3. 49 



Mesorhoea nov. gen. 



Tins genus bears an almost exact resemblance to Solenolambnt? in the 

 form and armature of the carapax, the character of the feet, and that of 

 the pterygostomian and hepatic channels, except that the latter are 

 deeper. It differs, however, in the very important point that the affe- 



