no ANIMAL LIFE PAST AND PRESENT. 



lived on in India into the human period, and thus have 

 given rise to the old Sanscrit legend that the earth 

 was supported by a gigantic elephant standing upon 

 the back of a still more gigantic tortoise ; the legend 

 being, however, discreetly silent as to what constituted 

 the support for the tortoise. 



In conclusion, we may say a few words as to the 

 classification of Ohelonians, leaving, however, out of 

 consideration the leathery-turtle and its allies, in 

 regard to the position of which there has been a con- 

 siderable amount of discussion. Ordinary Chelonians 

 are readily divided into two great groups, according 

 to the manner in which the head is retracted within 

 the shell. Thus, in the land- tortoises (Fig. 27) and 

 their allies, the head is drawn directly within the 

 margin of the shell by the bending of the neck in an 

 S-like manner in a vertical plane. The plastron of 

 this group is generally characterised by the absence 

 of the unpaired intergular shield (Fig. 29), so that the 

 two gular shields meet in the middle line. This 

 group, as we have already mentioned, includes, with 

 the exception of the soft tortoises, all the tortoises of 

 the Northern Hemisphere and also the marine-turtles ; 

 but it is by no means confined to this hemisphere, 

 although totally wanting in Australia. The name 

 Cryptodirans, or hidden-necked tortoises, is applied 

 to the members of this group. In the second great 

 group, on the other hand, the neck is bent sideways, 

 so that the head, when retracted, lies on one side of 

 the front aperture of the shell near to one of the legs j 



