1917.] vS. Kemp : Notes on Crustacea Decapoda. 225 



'JA2-I Kanaiofunofe, Backerp-uny-e Disl., 

 Bengal ... ... ... 



^^-i^ R. Hughli, Calcutta ... 



S^l^ Dhappa, near Calcutta 



-^-5-^ Ching-rig-hatta, near Calcutta 

 10 00 



^^Y^ Karnaphuli R., Rangamati, Chitta- 



gong Hill Tracts 



~jr^ Pazudaung and Dala Creeks, Ran- 

 goon, Burma 



" ^ ^ " Moulmein R., Burma. 



^-jj— Gying R., nr. Moulmein, Burma ... 



The species occurs in water that is quite fresh as well as in 

 that of low salinit}'. At Chingrighatta it was obtained in water of 

 specific gravit}" i*ooi5 and it is evidently not uncommon in the 

 Gangetic delta, occurring also in the estuaries of the Sitaung and 

 Moulmein rivers in Burma. It has, however, been taken at places 

 far remote from tidal influence. Rajmahal is some 350 miles b}^ 

 river from the sea, while Mirzapur in the United Provinces is 700 

 miles by river from the coast and nearly 400 miles in a direct line 

 from the sea. 



Leander potamiscus, sp. nov. 



This species resembles L. fluminicola in the absence of the 

 branchiostegal spine and in the great length of the carpus of the 

 second peraeopods ; it may be distinguished by the following 

 characters: — 



(i) The rostrum is longer, extending beyond the tip of the 

 antennal scale by two fifths or one half of its length. The basal 

 crest is low and bears from 7 to 10 teeth, ^ the hindmost being 

 situated on the carapace behind the level of the orbit. On the 

 upper side of the apex there are from i to 3 small teeth, usually 

 2, and there is not infrequently an additional tooth between these 

 and the foremost of those that form the basal crest. The teeth 

 on the lower margin are more numerous, from 6 to 10* (text- 

 fig- 7)' 



(ii) The finely-cut longitudinal groove on the carapace, just 

 above the position usually occupied b}^ the branchiostegal spine, 

 is particularly well defined. 



(iii) The peraeopods are all more slender. The first pair 

 reaches about to the end of the antennal scale, the carpus being 

 two and a quarter or two and a half times the length of the chela. 



(iv) The second peraeopods reach beyond the scale by the 

 chela and a portion (sometimes as much as one third the length) 

 of the carpus. The chela is one fifth shorter than the ischium 

 and about one half (sometimes a little more, sometimes a little 



t Of twenty-two specimens five have 7 teeth on the basal crest, twelve have 8- 

 tour have g and one has 10. 



2 Of twenty-two specimens one has 6 inferior teeth, five have 7, ten have 8, 

 five have 9 and one has 10. 



