in the Fish Gallery of the Indian Museum. 83 



known Indian species two occur in the Atlantic, one of 

 these being also found in the Mediterranean. 



Family II. Bhinobatidce [Cases 35-36]. 



In this family the form of the body is still Shark -like, 

 but the broadening- of the pectoral regions, which is so 

 characteristic of the Rays, is becoming manifest. The 

 snout is produced, but not nearly to such an extent as it 

 is in the Saw-fishes,, and it has no teeth on the edges. 

 Of the six known Indian species two, namely, Rhinobatus 

 halavi and R. columns, also occur in the Atlantic and 

 Alediterranean. 



Family III. Torpcdinidce [Case 33]. 



In this family the form of the body is rather more 

 Ray-like than Shark-like, the pectoral region being 

 much broadened to form a disk, from which however the 

 tail is not yet sharply delimited. On either side of the 

 disk, between the head and the pectoral fins, is an 

 " electric organ," the shock from which can disable 

 enemies and, perhaps, can also overcome prey. A dis- 

 section of the electric organ of one of the Indian species 

 is shown in Case 11 : it is seen to consist of a multitude 

 of vertically-placed hexagonal prisms, and to be supplied 

 by several enormous nerve-trunks. Three Indian species 

 of Electric Rays are known, namely, Narcine ttmlei and 

 Astrape dipterygia from shallow water, and Benthobatis 

 moresbyi from 430 fathoms. The skin of the Electric 

 Rays is quite smooth. 



Family IV. Rajidce [Case 34]. 



In the true Rays the head, trunk, and pectoral fins 

 together form a broad flat disk, from which the tail is 

 sharply marked off. The skin may be almost smooth, 

 but is more often furnished with prickles and definitely- 



