4io 



Memoirs of the Indian Museum. 



[Vol. V, 



This large species of fringe-tailed sting-ray is found everywhere in the lake- 

 system and always in very large numbers in the main area. It breeds in the lake. 

 Together with Trygon fluviatilis (H.B.), it has long been known to produce its young 

 in fresh water in India (Journ. Asiat. Soc. Bengal (n.s.), VI, p. 497). 



The measurements of two embryos are given below; one, a male, is very 

 young, while the other — a female — is almost fully formed. The disk of the younger 

 embryo is much longer than broad, in the advanced embryo it is as broad as long, 

 while in the normal adult it is rather broader than long. 





Embryo 9 . Barkul, 

 tember 1914. 



Sep- 



Embryo tf . Patshanipur, 

 March 1914. 





mm. 





mm. 



Length of disk 



120 





22 



Breadth of disk 



120 





17 



Interorbital distance 



30 





6 



Snout 



30 





6 



Mouth to vent 



100 





17 



Tail 



320 





33 



Umbilical cord 



35 





12 



Yolk sac 



5x2 





10x3 



Filament 



None. 





Numerous entering gill-slits. 



The food of this species consists chiefly of fish and prawns. In one instance the 

 stomach was found full of weed, which had probably been swallowed for the sake of 

 young molluscs (Modiola undulata) attached to it. 



The following Cestodes l were found in the alimentary canal of specimens taken 

 in the lake : — 



Phyllobothrium pammicrum , Shipley and Hornell. 



Parataenia medusia, Ijnton. 



Calliobothrium eschrichtii , Van Ben. 



The Trematode Anaporrhutum largum, Iyiihe, was found in the body cavity in two 

 cases (Southwell, op. cit., p. 335). 



The Ray appears to have no fixed breeding-season. 



In fine weather individuals often lie just below the surface of the water gently 

 undulating their pectoral fins. 



Distribution: — Indian Ocean, Red Sea, East Indies. 



1 See Southwell, Rec. Ind. Mus., XI, p. 331. 



