Genus and Species of Land- Crabs. 189 



in the structure of the epistoma, which in them is of great 

 length from before backwards and nearly horizontal, thus 

 differing remarkably from the Ucaince, in which it is short 

 and nearly vertical. This part has in Pelocarcinus been de- 

 scribed by Milne-Edwards * as " grand, completement h 

 decouvert et confondu en arri^re avec le palais;" and it 

 appeared to me to pass insensibly into the endostoma or 

 " palate " in Hylceocarcinus also until I had removed the 

 thick clothing of coarse hairs that obscured the parts, when I 

 found no difficulty in distinguishing them. It is also a notable 

 fact that the three most closely allied species of the former 

 (viz. Gecarcinus ruricola, Pelocarcinus Lalandei., and Hylceo- 

 carcinus Hiimei) have six rows of strong spines to the terminal 

 joints of the walking-legs ; and I would also draw attention 

 to the shallow yellow scars situated in all three on each side 

 of the eye and on other parts of the carapace — tell-tale marks 

 of their descent from a common ancestor ! 



Hyl^OCARCINUS t, n. gen., Wood-Mason, 

 Proc. As. Soc. Bengal, August 1873, p. 161. 



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

 the genera Gecarcinus 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 ex- 

 ternal 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 Hylaio- 

 carcinus the similar but stouter pillar-like projection that 

 carries these joints at its summit extending much further 

 tOAvards 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 Pelocarcinus they are completely 

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



* Arch, du Mus. 1855, vol. vii. pi. xv. 6g. 2 a. 

 t vXalos, Sylvester, et KupKivos, cancer. 



