THE SHARKS AND RAYS iii 



been taken intact from its stomach. Dubois * has observed 

 that the female torpedo gives shocks while the young are still 

 unborn, but abstains from doing so as soon as they are born 

 and so long as they remain near her. These facts perhaps 

 warrant three inferences : that the shock is a voluntary act ; 

 that the fish knows the danger to which her young would 

 be exposed ; and that she has maternal affection. 



Trygonidae 



The Stingray [Trygon pas tinned) has a yet more formidable 

 weapon than any of the foregoing, in the shape of a lono- 

 serrated dagger carried on the tail. Stingrays of 80 lb. have 

 been taken on our coasts, and in such a fish the dagger, if 

 intact, would measure half a foot or more. Whether this 

 frightful spike is provided, like the fangs of some snakes, 

 with venom does not appear to have been satisfactorily deter- 

 mined ; but such provision would scarcely seem to be necessary, 

 since it is in any case capable of inflicting a very serious 

 lacerated wound. 



In the stingray, the wing-like pectoral fins of the order 

 are still more highly developed than in most, completely 

 enveloping the head, which is merely distinguished by standing 

 above the body. The spiracles are large and lie behind the 

 eyes, the latter being rather small. The teeth are small and 

 lie in several rows. The tail is long and whip-like and has 

 no fin, but there is a fold of skin at the base of the spine. 

 It is said that the latter is replaced after injury by others that 

 lie behind it. The body is smoother than that of most rays, 

 though there may be a few tubercles on the disc. In colour 

 the upper surface is similar to the sand or mud on which 

 the fish resides. It probably lies for some time in the same 

 spot ; at any rate, the writer has seen pits left by its body 

 in the muddy banks of Queensland rivers. 



* Ann. Soc. Linn. Lyon, 1899, p. 80. 



