Oarcinological Fauna of India. 181 



flated club-shaped palm : in the female very short and slender. Ambu- 

 latory legs long, with remarkably thin compressed joints : some of the 

 legs spiny. 



Abdomen in both sexes with all the segments separate. 



This genus appears to be very closely related to Macroclieira. 



Platymaia wyville-thomsoni, Mi era. 



Platymaia xoyville-thomsoni, Miers, 'Challenger' Brachyura, p. 13, pi. ii. fig. 1. 

 Platymaia ivyville-thomsoni, Wood-Mason and Alcock, Ann. Mag. Nat. Hist., 

 March, 1891, p. 258, and May, 1894, p. 401. 



Carapace transversely sub-circular with the cervical grove well 

 defined: its surface ranging from spinate (in the young) to nearly 

 smooth (in old adults). The rostrum, which is so short as not to break 

 beyond the general outline, consists of three stout spines of equal size, 

 the middle one being the horizontally projecting interanteunulary 

 spine. 



The hepatic region of the carapace bears (in the adult) a nearly 

 vertically disposed row of three spines, against the upper one of which 

 the eye is retractile. 



The eye-stalks are short, and the eyes large and oval. The antenna? 

 are about one-third the length of the carapace, and are plainly visible, 

 in almost the whole of their extent, from above : the joints of the pedun- 

 cle are short slender and cylindrical, the basal joint being perfectly free. 



The external maxillipeds have the meropodite narrow (about half 

 the breadth of the ischiopodite) and giving attachment to the coarse 

 palp at the summit : both meropodite and ischiopodite are spiny. 



The chelipeds vary considerably according to sex : in both sexes 

 they are spiny up to the base of the fingers ; but whereas in the female 

 and young male they are much slenderer than any of the legs and 

 are not longer than the carapace, in the adult male they are from two 

 to three times the length of the carapace and are much stouter than 

 any of the legs — especially as regards the palm, which is swollen and 

 club-shaped. The 2nd to 5th pairs of legs are long and slender, with 

 the joints thin and compressed, the propodites being blade-like. 

 The 2nd pair, which are from 3f (female) to 5| (male) times the 

 length of the carapace, are remarkable for their propodite and 

 dactyl us, the front edge of which bears a double comb of enormous 

 spines, the posterior edge also being spinulate : both edges of the 

 merus and carpus also are distantly spinulate. The 3rd and 4th pairs 

 have the front edge of the merus distantly spinulate, and they, as well 

 as the 5th pair, have the front edge of the razor-like merus closely 

 fringed with long stiff hairs. 

 27 



