1895.] A. Alcock — Carcinological Fauna of India. 203 



The external maxillipeds have the ischium and merus somewhat 

 concave. 



The chelipeds vary according to sex. In the adult male they are 

 longer than the carapace and rostrum, and are far stouter than any of 

 the other legs : the carpus is enlarged and sculptured, the palm is 

 broadened, as well as somewhat carinate along both edges and strongly 

 produced at the postero-inferior angle, and the fingers are opposable in 

 their distal half only : in the female and young male they are shorter 

 than the carapace with the rostrum, and are hardly stouter than the 

 other legs ; all the joints are subcylindrical, and the fingers are apposa- 

 ble in the greater part of their extent. 



In both sexes, the merus of all the legs, including the chelipeds, 

 has a spine or tooth at the far end of its upper margin. The 2nd pair 

 of trunk-legs, which are the longest, are, in the male, nearly twice the 

 length of the carapace and rostrum, but in the female are considei'ably 

 shorter. 



Loc. Andaman Sea, 130 to 56.1 fathoms. 



Scyramathia rivers-andersoni, n. sp. 



Carapace closely covered with peg-shaped hairs with long setae 

 interspersed : legs with few setae. The carapace, which is pyriform and 

 somewhat inflated, has, besides a supra-ocular tooth and a sharp post- 

 ocular process, and besides a salient hepatic spine, and a still more 

 salient lateral epibranchial spine (about two-fifths the greatest breadth 

 of the carapace in length) six sharply conical tubercles evenly and 

 equidistantly arranged in a circle round a central caradiac tubercle : 

 of these the most posterior oveimangs the middle of the posterior border, 

 while the most anterior, which is situated far back on the gastric 

 region, is flanked on either side by a very faint eminence. 



The rostrum consists of two slender divergent horns, the length 

 of which in the male is about three-quarters, in the female about 

 two-thirds, that of the rest of the carapace. 



The eyes are small, and though freely movable forwards are not 

 retractile backwards further than to impinge against the summit of 

 the post-ocular process of the carapace. The basal antennal joint, 

 which is of no great width, is sharply truncated : the mobile portion of 

 the antenna is freely exposed on either side of the rostrum. 



The chelipeds in the fully adult male (but not in the young male) 

 are much stouter than the other legs, and are as long as the carapace 

 and rostrum ; their merus is prismatic with knife-like edges, the upper 

 edge ending in a spine ; their carpus is bicarinate, the outer carina 

 being very prominent ; the hands, which form nearly half their total 

 J. II. 26 



