76 GIANT FISHES 



All the species are viviparous, or, more accurately, ovo- 

 viviparous, the eggs being hatched within the body of the 

 mother. Some of the Sting Rays make elaborate provision 

 for the nutrition of the embryo, and there may be developed 

 a complicated connection with the walls of the uterus, recalling 

 the placenta of mammals. The walls sometimes grow out 

 into long, filamentous processes, which are richly supplied 

 with blood-vessels and secrete a creamy nutritious fluid. 

 This fluid may be absorbed by the blood-vessels of the yolk-sac 

 of the embryo, or may be taken directly into its stomach by 

 way of the mouth or spiracles. 



None of the Sting Rays are of any value as food, the flesh 

 being generally rank and disagreeable. A few of the rougher 

 kinds provide a good shagreen. In Ceylon the tails were 

 formerly dried and used, after having been treated with oil to 

 make them supple, as whips for punishing criminals, but this 

 is now prohibited by law. It is recorded that the fishermen 

 of Wales believe that the oil from the liver of a Sting Ray 

 is good for burns and other wounds. 



EAGLE RAYS. 



(Family Myliobatid^.) 



Closely related to the Sting Rays. The head, trunk and 

 pectoral fins are joined to form a broad, lozenge-shaped 

 disc, from which projects a more or less long, slender, whip-like 

 tail, which has a single small dorsal fin near its base. Behind 

 this fin there is generally i (sometimes more) serrated spine, 

 similar to that of the Sting Rays but usually smaller. The 

 pectoral fins are very muscular, and their front edges are 

 much indented, so that they have the appearance of being 

 missing on the sides of the head and of reappearing at the 

 front to form a fleshy pad. The teeth are large, flat, and 

 form a tessellated pavement in each jaw ; there is always a 

 row of broad teeth in the centre of the jaw, and usually 3 

 rows of narrow teeth on each side of the centre row. The 

 skin is almost or quite smooth. 



These are all large rays and are found in most warm seas. 

 Fossil remains date back at least as far as the Eocene period. 



