Sharks and Rays 



669 



Fholohj) ir. Suville-Kent, F.Z.S.] 



SHOVEL-NOSED SKATE. 

 Known also as the Halavi Eay. 



[MUjord-Ofi-Sea. 



its trivial name. All these 

 rays, in fact, have some form 

 or other of formidable offen- 

 sive and defensive apparatus. 

 The Sting-ray has on its 

 tail a fearful serrated dagger, 

 6 or 8 inches long in hu-ge 

 examples ; while the TourE Do- 

 or Numb-fish has electric 

 organs in the head, with the 

 aid of which it can give a 

 shock sufficiently strong to 

 paralyse the fishes on wdiich 

 it feeds. 



Two interesting peculi- 

 arities of the rays deserve 

 notice in concluding this 

 chapter. The first is that 

 their egg-purses, instead of 

 attaching themselves with 

 filaments to weeds and rocks, 

 like those of the sharks, are 



provided with a sticky secretion which answers the same purpose of anchoring them in 

 security from currents that would carry them out into deep, cold water. The second is 

 the sexual difference in the teeth, which are pointed in the male and flat in the female. 

 "Whether this difference in the teeth (which may be likened to that between the bills of 

 the male and female Huia-bird of New Zealand) indicates a corresponding difference in food, 

 or, on the other hand, some co-operation between the sexes in jwocuring it, is an interesting 

 question that our present slight knowledge of the habits of these fishes does not enable us 

 to answer. 



Finally, attention must be drawn to the remarkable transformation which the breast-fins 



and tail have undergone. The 

 former have developed into 

 powerful swimming-organs, 

 locomotion being effected by 

 their undulatory movements, 

 instead of by similar move- 

 ments of the whole body, or 

 by side-to-side motions of 

 the tail, as in other fishes. 

 Whilst the latter, no longer 

 used in swimming, has either 

 been reduced to a mere vestige, 

 as in the Horned Ox-eay, 

 or has become developed into 

 a long and tapering " whip- 

 lash," provided with a poison- 

 spine. In such cases the long 

 tail is used to encircle prey, 

 and at the same time to force 

 the victim on to the deadly 



PAINTED bl.AlL. _ •' 



So called on account of its conspicuous coloration, i 



U ( 1/ ' b J. 



