1898.] A. Alcock — Carcinological Fauna of India. 125 



Outer orbital angle inconspicuous, orbits small, the upper margin 

 with a narrow cleft. 



Front very prominent, lamellar, a little sinuous at the sides, pro- 

 minent towards the middle where there is a linear fissure. 



Chelipeds unequal: the hand has the inner surface flattened, the 

 upper border obtusely crested, and the outer surface rugose : the wrist, 

 which has its outer border much dilated, is equally rugose. 



The legs are weak and smooth, the dactylus being a little com- 

 pressed. 



Carapace yellowish, very symmetrically marked with numerous 

 reddish-brown lines, some of which run obliquely from the antero- 

 lateral borders towards the front and towards the middle line, while 

 others run from the posterior border forwards to the cardiac region. 



There are no specimens in the Indian Museum collection. 



Hoploxanthus, n. gen. 



Carapace hexagonal, moderately broad, moderately convex fore and 

 aft, its regions all well defined, and to a certain extent subdivided. 



The anterolateral borders are thin and crest-like and are on a 

 much lower plane than the rest of the carapace, they end either in both 

 sexes or in the female only, in a large horizontal lateral epibranehial spine, 

 and may either be cut into large triangular teeth or may be only 

 obscurely notched. 



Postero-lateral borders straight, moderately convergent, about as 

 long as the antero-lateral. 



Front lamellar, prominent, horizontal, notched in the middle line, 

 about a fourth to two-sevenths the greatest breadth of the carapace. 



Orbital margin with two faintish notches or suture lines above, and 

 with a small triangular gap just below the outer angle : the inner angle 

 of the lower orbital margin forms a strongly-projecting tooth : the outer 

 •orbital angle is confluent with the antero-lateral margin. 



The antennules fold obliquely. The basal antennal joint is rather 

 slender and meets the front : the flagellum, which is about as long as 

 the major diameter of the orbit, is lodged in the orbital hiatus. 



The anterior edge of the external maxillipeds is almost transverse. 



Chelipeds unequal, fingers sharp pointed : legs rather slender. 



No ridges, defining the efferent branchial channels, on the plate. 



The abdomen of the male consists of seven separate segments, the 

 last segment being no longer than the longest of the others. 



This genus is closely allied to Xantho and Cycloxanthus, it is also 

 related not distantly to Halimede and to Lophozozymus. 



