igoQ.] N. Annandai^e : Report on the Batoidei. 33 



Mouth. — The jaws are somewhat curved as a whole and regularly but not very strongly 

 undulate. The teeth are small and white ; the transverse ridge is low and 



KiG. 6. — Teeth of Trygon imbricata (enlarged). From preparation in canada balsam. 



somewhat irregular, the surface of the tooth posterior to it being decidedly con- 

 cave. There are two short processes on the floor of the mouth, occasionally with 

 a minute papilla between them. They are situated much nearer to one another 

 than either is to the angle of the mouth. 



At first sight the form described by Bloch and Schneider as Raja imbricata is 

 very distinct from Müller and Henle's Trygon walga. Indeed, so long as I had only 

 examined a comparatively small series of specimens, I was prepared to regard them at 

 least as distinct varieties. Recently, however, I have had an opportunity of ex- 

 amining a large number of living specimens, among which I find every gradation be- 

 tween the two forms. Shortness of tail is not invariably or even usually correlated 

 with any peculiarity in the denticles, nor is the exact form of the disk correlated with 

 either character. Every possible gradation is found between a distinct caudal fold 

 and a complete absence of any such character. Nor is any one peculiarity peculiar to 

 either sex. Except that the young has a relatively wider disk, a longer tail and a 

 paler colour, and usually fewer denticles on the disk, than the adult, there is no ex- 

 ternal difference between them, and I have seen two embryos from one mother which 

 differed considerably as regards length of tail. 



T. imbricata appears to be, in the strict sense of the phrase, a Httoral and estuarine 

 species. Few specimens have been taken in water even so deep as 15 fathoms by the 

 " Golden Crown,' ' but large numbers are captured in the winter season on the Orissa 

 coast at Puri by means of seine-nets worked from the shore. The flesh is only eaten 

 by the lowest castes of the Hindus. 



Trygon zugei (Müller and Henle). 



Size small (largest specimen 31 cm. across disk, smallest 8-5 cm.). 



Disk slightly broader than long ; the pectoral angles broadly rounded ; the greatest 

 transverse diameter situated about half way between the base of the tail and the 

 tip of the snout, which is sharply pointed and much produced, its length from 

 the eyes being more than three times as long as the distance between the eyes. 

 Eyes nearly as large as the spiracles. 



