1899.] A. Alcock — Oarcinological Fauna of India. 31 



tnerns of the external maxilHpeda is not produced in 



a lateral direction] Hellenus. 



V. Carapace moderately broad, distinctly convex, rounded 

 postero-laterally. Front projecting beyond the inner 

 supra-orbital angles : the last spine of the antero- 

 lateral borders slightly the largest. Orbits large, with 

 strong dorsal inclination. Basal antenna-joint longitu- 

 dinally grooved on ventral surface. No free prolonga- 

 tion of the epistome in the middle line : no lateral 

 expansion of the autero-external angle of the merus 

 of the external maxillipeds. Hand much slenderer than 

 the arm Lupoc ycloporus. 



Key to the Indian species of the genus Neptunus. 



I. Hand either more, or but little less, massive than arm : — 

 A. Last spine of antero-lateral border much the 

 largest : — 



1. Posterior angles of carapace rounded (Neptu- 

 nus): — 

 i. Antero-external angle of merus of exter- 

 nal maxillipeds rounded : — 



a. No spine on the posterior border 



of the arm N. sanguinolentus. 



b. A spine at far end of posterior 



border of arm .... , N. pelagicus. 



ii. Antero-external angle of merus of exter- 

 nal maxillipeds strongly produced in a 

 lateral direction (Amphitrite) : — 



a. No spot on dactylus of last pair of 



legs N. gladiator. 



h. A spot on dactylus of last pair of 

 legs : crests of hands and abdomen 

 with a pearly sheen N. argentatus. 



c. Spine at inner angle of wrist two- 

 thirds as long as palm N. petreus, 



2. Posterior angles of carapace square or spini- 

 form (Hellenus) : — 



i. Posterior angles square : front cut into 3 



teeth N. tenuipes. 



ii. Posterior angle spiniform : front cut into 

 4 teeth : — 



a. Two distinct spines on posterior 

 border of arm : — " 



■jr. After half of distal border of 

 merus of last pair of legs 



finely serrulate N. hastatoides. 



&, After half of distal border of 

 merus of last pair of legs 

 smooth N. andersoni. 



