2G0 J. Wood Mason — On a N'ew Oenus of Lander abs. [No. 4<, 



Front not united to tlie internal suborbital lobes as it is in the genera 

 Gecarei7ius and Pelocarcinus^ but separated from them by spaces at least as 

 wide as the deep bold fissures that divide to their bases the internal from 

 the external suborbital lobes ; into these interspaces project the flagella of 

 the antennae, the basal joints of which appendages lie tightly wedged 

 between the internal margins of the internal suborbital lobes and the 

 epistoma. The third joint of the external maxillipeds with an obtuse-angled 

 emargination in its anterior border ; the external margins only of the first 

 of the three terminal joints is barely visible externally when the appendages 

 are properly closed, its external surface being flattened for movement upon 

 the inner face of the preceding joint : in Gecarcinus these terminal joints are 

 completely hidden from view, the angular process that projects like a pillar 

 in demi-relief from the inner face of the third joint and supports them, 

 ending abruptly so very far short of the anterior margin of the joint : in 

 HyloBOcarcinus the similar but stouter pillar-like projection that carries 

 these joints at its summit extending much farther towards the extremity of 

 the joint than it does in Gecarcinus but certainly failing to reach it, these 

 joints can consequently be only partially visible : in Felocarcinws they are 

 completely visible, being articulated to the apex of the third joint. 



HYLiEOCAECINTJS HtJMEI, n. sp. 



The carapace is at once distinguished from that of Felocarcinus 

 Zalandei, M.-Edw. by its more arched outline in front, and by the two 

 rounded tubercles on the mesogastric lobe which, as in Gecarcinus ri^Hcola, 

 is limited off antero-laterally from the rest of the gastric region by very 

 shallow depressions passing off from the hinder end of the profoundly-deep 

 median groove and joining the branchio-gastric groove on each side ; the 

 straight line representing its greatest breadth crosses it just in front of these 

 tubercles ; in front of this imaginary line its upper surface is very convex 

 and much swollen everywhere, but behind it flat ; it is just perceptibly 

 angulated on each side for a short distance beyond the external margin of 

 the orbits, these angulations corresponding to the lines of spiniform tubercles 

 seen in the sanie position in Gecar chins 7niricola. The outer slopes of the 

 branchial regions, both anteriorly and posteriorly, and the floors of the 

 branchial chambers, all the inflected portions of the carapace in fact, 

 covered with squamiform tuberculated lines which, fine and delicate above, 

 become shorter and coarser as they approach tlie bases of the legs and the 

 buccal frame. The anterior is divided by a shallow transverse impression 

 slightly interrupted in the middle line from the posterior cardiac lobe, which, 

 just as in the rest of the Gecarcindce^ is much expanded posteriorly between 

 the bases of the posterior pair of legs. 



The interantennulary septem is formed mainly by the subfrontal lobe, 



