BATOIDEI. 35 



with lateral cusps. Fins the origin of the first dorsa is just 

 posterior to the base of the ventral, the anterior edge of the former 

 exceeds the length of its base, which latter distance equals the 

 length between the t\vo dorsal fins, both of which have their 

 anterior and upper edges rounded; the second fin somewhat 

 smaller than the first and ending some distance anterior to the 

 origin of the anal. Anal notched, terminating close to the caudal 

 fin, which is also notched posteriorly, and is contained about 5 

 times in the total length. Erom one to three smooth or tuber- 

 cular ridges may exist along the back, or may be entirely absent. 

 Colour this varies exceedingly : usually grey with dark, or even 

 black, cross-bands, which may or may not include white spots ; 

 sometimes the cross-bands break up into spots or bands, having 

 dark edges ; or the fish is simply of a reddish-brown colour. 

 Hob. Seas of India to the Malay Archipelago, and beyond. 



Suborder B. BATOIDEI. 



Spiracles present ; gill-openings in five pairs, and on the ventral 

 surface of the body. Body depressed, forming, with its largely 

 developed pectoral fins, a more or less flat disk, and usually having 

 a thin and slender tail. Dorsal fin, when present, in the caudal 

 portion of the body ; anal absent. 



Some of these fishes approach the sharks in external form, the 

 tail portion not being so sharply contracted behind the trunk as in 

 most rays. 



Skates and rays exist in enormous numbers in the Indian seas, 

 where they attain to a great size, and some are dreaded by fisher- 

 men because of the wounds inflicted by their caudal spines, while 

 others cause great injury to the oysters and other mollusks. 

 Skates are gregarious, and may suddenly arrive, to the dismay of 

 the owner of an oyster-bed, as they appear to remain so long as 

 any mollusks are to be obtained. Eays lie concealed in the sand, 

 and are reputed to be able to suddenly encircle fish or prey 

 swimming above them with their long whip-like tails, and then 

 wound them with their serrated tail-spines. They are observed in 

 aquaria to cover their victims with their expanded body and sub- 

 sequently convey their prey to their mouths by movements of 

 their pectoral fins. Their skins were formerly valuable as shagreen, 

 being considered superior to those of sharks. Irrespective of this 

 use, they are occasionally employed as rasps or sand-paper, to give 

 the first surface to wood or horn which it is desired to polish. 

 Their fins are exported, along with those of the sharks, to China, 

 where they are in request for soups, while from their livers an oil 

 is extracted (see pp. 5, 6, ante). 



The thin horny cases, inside which are the foetal rays, are more 

 quadrangular in form and comparatively smaller than what are 

 observed among the sharks ; such cases have a horn-like projection 

 from each corner. 



