Carcinological Fauna of India. 209 



long as the carapace 'plus half the lustrum ; the fingers, which are hardly 

 one half shorter than the short palm, are arched and meet only near 

 their tips : in the female the chelipeds are rather more slender than 

 the other legs, are only as long as the post-ocular portion of the cara- 

 pace, and have nearly straight fingers that meet in the greater part of 

 their extent. 



The second pair of legs, in both sexes, are considerably longer than 

 the chelipeds and than any of the three last pairs : the dactyli of all 

 the ambulatory legs are stout, recurved, and serrated along the posterior 

 margin. 



In the Museum collection are numerous specimens of both sexes, 

 from Ceylon and Mergui. 



Hyastenus hilgendorfii, de Man. 



Hyastenus hilgendorfii, de Man, Journ. Linn. Soc, Zool., Vol. XXII. 1888, p. 14, 

 pi. i. figs. 3 and 4. 



This species much resembles H. pleione, but is distinguished by 

 the following constant characters : — the carapace is but faintly tuber- 

 culated, and, in particular, there is no tubercle between the gastric and 

 cardiac regions : the dactyli of the ambulatory legs are very strongly 

 toothed, instead of merely serrated, along the posterior margin : in the 

 male the rostrum is nearly two-thirds the length of the carapace, and 

 the chelipeds are as long as the carapace and rostrum combined, and 

 nearly as long as the second pair of trunk-legs, — this being largely 

 due to the increased length of the palm. 



Carapace subpyriform, and, like the rostrum and legs, pubescent ; 

 the regions moderately well-defined. 



The gastric region is either quite smooth, or presents three faint 

 elevations disposed in a triangle base forwards. There is a small 

 tubercle near the middle of the intestinal region ; and a line of °ran il- 

 lations along the boundary between the hepatic and pterygostomian 

 regions, which line is continued backwards, along the side of the branchial 

 region, to end at a distinct lateral epibranchial spine : there is also a 

 more or less distinct line of granules on the dorsal aspect of the epi- 

 branchial region. 



The rostrum consists of two divergent spines, the length of which 

 in the male is nearly two-thirds that of the carapace proper, but is con- 

 siderably less in the female. Basal antennal joint with the outer mar- 

 gin sinuously curved. 



The trunk-legs have the surface somewhat uneven : the chelipeds 

 in the male are much stouter than the other legs, and are as long as the 

 55 



