Carcinological Fauna of India. 285 



Family Hymenosomidj;. Small marine and estuarine Catometopes h'2.il 

 taving a curious superficial resemblance to some of the Oxyrhynch 

 crabs of the Inachine subfamily, a resemblance heightened by the fact 

 that the epistome is sometimes nearly as long as broad. The palp of 

 the external maxillipeds articulates near the antero-external angle of 

 the merus, but as the antero-internal angle of the merus is sometimes 

 truncated the true relations of the palp ai'e often not quite clear : the 

 exognath is slender and partly or entirely concealed. There are no 

 orbits and the eyes are exposed and little retractile. [Carapace thin, 

 flat, triangular or subcircular, not very well calcified, usually produced 

 to form a horizontal rostrum. Antennular foss« shallow and ill defined. 

 Antennal peduncle slender. Buccal cavern square, the ischium of the 

 external maxillipeds well developed]. Male openings sternal. 



Family Palicid^. Small Catometopes having a sort of Dorippe 

 appearance. The Indian members of tlie family are found among coral- 

 and shell-shingle, at a moderate depth, and have a kind of protective 

 resemblance to an eroded flake of coral rock. The external maxillipeds 

 close the buccal cavern ventrally but not anteriorly : their merus is a 

 very small joint articulating with the retreating antero-external angle 

 of the ischium, and carrying the palp at the middle of the oblique-lying 

 anterior (or inner) border, their exognath is not concealed and is rather 

 broad. The interantennular septum is a thin plate. The orbit has 2 or 

 3 deep gaps in the upper border. Front of moderate breadth, little or 

 not at all deflexed : antennal flagella of good length : epistome absent : 

 abdomen of male narrow. Compared with the other 3 pairs, tJie 4<th 

 (last) pair of legs, tohich are dorsally situated, are rudimentary in all the 

 Indian species. Male openings sternal : female openings placed far 

 forward on the sternal segment corresponding with the first pair of ambula- 

 tory legs (2nd perseopods). 



Family PxENOPLACiDa:. Represented by an aberrant Catometope 

 found only in Indian Seas at a depth of 100 to 250 fathoms. The 

 external maxillipeds are slender and subpediform, not nearly covering 

 the buccal cavity : their palp articulates with the summit of the slender 

 merus : their exognath is of normal size and form, and is not concealed. 

 The interantennular septum is a thin rudimentary plate. The orbits 

 are very incomplete below. The front is a narrow, little deflexed lobe. 

 No distinct antennular fossae. Antennal flagella of good length. No 

 epistome. Abdomen of male narrow. Compared with the other 3 

 pairs, the last {fourth) pair of legs are rudimentary, being also placed close 

 together dorsally : the last segment of the sternum is also rudimentary. 



627 



