150 THE HISTORY OF ANIMALS. [s. VI. 



are excluded by the rupture of the shell. In the acantheas 1 

 galeos the ova are attached to the diaphragm above the 

 nipples ; and when the ovum descends, the young is attached 

 to it after it is set free. The reproduction of the alopex is 

 in the same manner. 



5. Most galei which are called smooth have the ova placed 

 between the divisions of the uterus, like those of the scylia ; 

 and as they surround it, they descend into each division of 

 the uterus, and they are produced, attached to the uterus 

 by an umbilical cord ; so that when the ova are taken out, 

 they appear similar to the embryo of quadrupeds. And the 

 long umbilical cord is attached to the lower part of the 

 uterus, each part, as it were, attached to an acetabulum ; 

 and to the middle of the embryo near the liver. And when 

 it is dissected, the food is like an egg, though the ovum be 

 no longer there. There is a chorion, and peculiar membranes 

 surrounding each of the embryos, as in quadrupeds. 



6. The head of the embryo when it is just produced, is 

 upwards ; but as it grows and reaches maturity, it is placed 

 downwards. The males are placed on the left, and the 

 females on the right, or there are males and females together 

 on the same side. The embryo, when dissected, resembles 

 that of quadrupeds, in having its viscera such as it has, as the 

 liver, large, and full of blood. In all the selache the ova are 

 placed high up, near the diaphragm ; many larger, and many 

 smaller : and the embryos are placed below, wherefore it is 



Erobable that such fish produce their young, aud copulate 

 *equently during the same month, for they do not produce 

 all their young at once, but frequently, and for a long while ; 

 but those that are in the lower part of the uterus are matured 

 and brought to perfection. 



7. The other galei both emit and receive their young into 

 themselves, and so do the rhine and the narca ; and a large 

 narca has been observed to contain eighty young in herself. 

 The acanthias is the only one of the galei which does not 

 admit its young into itself, on account of their thorns. 

 Among the flat fish the trygon and batos do not admit their 

 young, on account of the roughness of the tail. Neither 

 does the batrachus admit its young, on account of the size 

 of their heads, and their thorns ; and this is the only one 



is not viviparous, as I previously observed. These are 

 1 Squalus Acanthias. 



