MUSEUM OF COMPARATIVE ZOOLOGY. 153 



This genus differs from Calappa in the want of lateral expansions of the 

 carapax, and from Mursia in the want of lateral spines. From all the 

 genera of the family hitherto described it differs in its great facial width. 



Acanthocarpus Alexandri nov. sp. 



Carapax regularly convex, -with uneven surface, the protuberances 

 being arranged obscurely in five longitudinal rows anteriorly, the middle 

 ones of which form centrally and posteriorly three conspicuous ridges, 

 the lateral ridges terminating in the teeth of the postero-lateral margin. 

 The surface is uniformly, but not thickly, covered with minute, equal 

 granules, the interspaces between which are wider than the granules 

 themselves. The posterior margin is regularly arcuate, and bears a slight- 

 ly prominent tooth at the middle, and a slight wave in the outline on 

 either side. The lateral margin is unarmed, except by two or three slight 

 tuberculiform teeth near the orbit. The orbits are large, without fissures, 

 except the inner superior one, which is itself nearly obsolete ; orbital mar- 

 gin ciliated. The front is of moderate width, a little convex, but not 

 toothed, and is separated from the orbit by its lateral angle simply, and 

 not by any notch. The spine on the carpus of the cheliped is nearly half 

 as long as the carapax ; and above it, on the same joint, there is another 

 spine, stouter, but only one fourth as long as the first. Both these spines 

 are granulated. The hand is provided with a seven-toothed crest above, 

 and another, oblique, six-toothed crest on the outer surface, extending from 

 the base of the dactylus to the postero-inferior angle. On the latter crest 

 the posterior tooth is largest, and forms by itself a short crest, separated 

 from the other teeth by a considerable interval. Between the upper and 

 lower crests of the hand there are four or five tubercles scattered upon the 

 surface. Ambulatory feet naked, unarmed, with smooth polished surface. 



Dimensions of a male : Length of carapax, 0.31 inch ; breadth the same. 

 Off the Quicksands, January 23, 1869. Cast No. 2. 74 fathoms. 



Calappa marmorata Fabr. 



Cancer marmoratus Fabricius, Ent. Syst, II, 450 (1793). 



Cancer flammeus Herbst, Naturg. d. Krabben und Krehse, II, 161 ; pi. xl, 



fig. 2. 

 Calappa marmorata Fabricius, Suppl. Ent. Syst., p. 346. II. Milne-Edwards, 



Hist. Nat. des Crust., II, 104. Desbonne et Schramm, Crust, de la 



Guadeloupe, p. 51. 



Found at Key West, in from 2 to 5 fathoms. 



Calappa galloides Stm. 

 Calappa galloides Stimpson, Notes on N. American Crustacea, p. 25. 

 Found at Key West, in 4 to 5 fathoms. 



