1895.] 



A. Alcock — Carcinological 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. 



fi. Eostral spines as long as the 

 carapace, and nearly parallel 

 in their proximal half : cara- 

 pace indistinctly tubercu- 

 lated.. [H. seise.'] 



.Rostral 

 spines at least 

 as long as the -\ 

 carapace pro 

 per. 



I. Denuded 

 carapace 

 with nume- 

 rous tuber- ■{ 

 c le s , or 

 spines, and 

 erosions. 



2. Rostral 

 spines not 

 much more 

 than half the 

 length of the 

 carapace pro- 

 per. 



. 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- 

 al? 8 -ff. tenuicornis. 



fa. Numerous 

 tubercles for- 

 ming a cross 

 on the gastric 

 region: a me- 

 dian trans- 

 tuber- 



Legs coarse, 

 the mero- 

 podites of 

 all (includ-<{ 

 ing the 

 chelipeds) 

 nodular. 



verse 



cle in 



groove 



tween 



gastric 



card 



regions.. 



the 

 be- 

 the 

 and 



H. pleione. 



b. Gastric re- 

 gion almost 

 smooth : no 

 tubercle 

 tween 

 gastric 

 cardiac 

 l^ gions.... 



be- 

 the 

 and 



H. hilgendorfii. 



ii. Legs slend- 

 er, the me- 

 ropodites 

 smooth. 



fa. Carapace 

 elongate 

 closely cover- 

 ed with gra- 

 nules and tu- 

 bercles, with- 

 out spines JET. oryx. 



b. Conspicuous- 

 ly large spines 

 on the cardiac 

 and branchial 

 L. regions H. gmcilirostrii 



