Carcinologieal Fauna of India. 



207 



Chelipeds in the adult male enlarged : the second pair of trunk- 

 legs usually very much longer than the 3rd 4th and 5th pairs. 



The abdomen in both sexes consists of seven distinct segments. 



Key to the Indian species of Hyastenus. 



i. Rostral spines as long as the 

 carapace, and nearly parallel 

 in their proximal half : cara- 

 pace indistinctly tubercu- 

 lated [H. sebse.~\ 



Rostral 

 spines at least 

 as long as the <{ 

 carapace pro 

 per. 



I. Denuded 

 carapace 

 with nume- 

 rous tuber- «{ 

 cle s , or 

 spines, and 

 erosions. 



Rostral 

 spines not 

 much more 

 than half the 

 length of the 

 carapace pro- 

 per. 



\ 



I 



Rostral spines about twice 

 as long as the carapace, and 

 widely divergent from their 

 origin : carapace with nu- 

 merous tubercles, and with 

 large cardiac, branchial and 

 intestinal spines : a long ter- 

 minal spine on the merus of 

 of the second pair of trunk- 

 legs H. tenuicornis. 



a. Numerous 

 tubercles for- 

 ming a cross 

 on the gastric 

 region: a me- 

 dian trans- 

 verse tuber- 

 cle in the 

 groove be- 

 tween the 

 gastric and 

 cardiac 

 regions H. pleione. 



Legs coarse, 

 the mero- 

 podites of 

 all (includ-<{ 

 in g the 

 chelipeds) 

 nodular. 



Gastric re- 

 gion almost 

 smooth : no 

 tubercle be- 

 tween 

 gastric 

 cardiac 

 gions , 



the 



and 



re- 



s', hilgendorfii. 



ii. Legs slend- 

 er, the me- 

 ropodites 

 smooth. 



Carapace 

 elongate 



closely cover- 

 ed with gra- 

 nules and tu- 

 bercles, with- 

 out spines H. 



oryx. 



53 



Conspicuous- 

 ly large spines 

 on the cardiac 

 and branchial 

 regions H. gracilirostris. 



