62 RAIDJE; STING-RAY, THORNBACK. 



the length of twelve or even fifteen feet. This fish is very widely 

 distributed, being found in the arctic, antarctic, and tropical seas; 

 but it seldom approaches the shore. 



584. The true Rays^ typical of the family RAIDJE, have the 

 body so flattened, that the pectoral fins seem like a continuation 

 of it ; and these meet in front of the snout, and are prolonged 

 backwards as far as the ventral fins ; thus giving to the whole 

 body a nearly circular form. The eyes are situated on the upper 

 side of the body, as in the Flat-fish ( 564) ; but it will be ob- 

 served, that the plan of construction of the Rays and Skates, is 

 entirely different from theirs, the two margins being here com- 

 posed of the edges of the pectoral fins, whilst in the Flat-fish 

 they are formed by the dorsal and anal ; and the Flat-fish habi- 

 tually lying on one side, whilst the Rays, &c., lie on the abdo- 

 minal surface, where we find their mouth and gill-openings. 

 These fish live for the most part near the bottom of the water, 

 on beds of sand or mud. When disturbed, they glide along in 

 an undulating manner, with a slight motion of the pectoral fins ; 

 and if attacked, they defend themselves by lashing violently with 

 the tail, which is often furnished with sharp spines. In the 

 Sting-Ray (Trygon), the tail has a single 

 strong spine, notched on both sides. There 

 are several species, intermediate in form be- 

 tween the Sharks and Rays, by which the tw r o 

 families are connected. Most of the family 

 are extremely voracious, feeding on Fishes and 

 Crustacea, and on naked or testaceous Mol- 

 lusks. The teeth are flattened and lozenge- 

 shaped ; and so powerful are the iaws, that 



FIG. 285 STING-RAY. , 



they are capable of crushing the shell of a 

 Crab with the greatest ease. Some of the Rays produce their 

 young alive ; in those which lay eggs, these are deposited in a 

 horny case, like that of the Dog-fish. One of the most common 

 of the British species is the Thornback ; so named from the 

 skin of its back being covered with thorny tubercles, variable 

 in their number ; this fish is taken in abundance in the spring 

 and summer, when it visits the shallows for the deposition of its 



