IOO 



TORTOISES AND TURTLES. 



the other hand, all the American soft-tortoises, of which T. ferox is a well-known 

 example, differ by having only seven pairs of costal bones. Numerous representa- 

 tives of the genus occur in the Miocene and Eocene strata of Europe, as well as 

 in the Tertiary rocks of India and the United States. Two other members of 



the first subfamily, confined to Asia, 

 represent as many genera. Of these 

 Cantor's soft-tortoise (Pelochelys can- 

 tori), from India, Burma, and Malay ana, 

 has the sockets of the eyes placed 

 more anteriorly than in the type genus. 

 This forward position of the eye-sockets 

 is still more marked in the much elon- 

 gated skull of the great Indian chitra 

 (Chitra indica), where they are placed 

 close up to the nose. 

 Granulated soft- The three remaining 

 Tortoises, genera of the family are 

 characterised by the sculpture of the 

 shell generally taking the form of small 

 pustules, and thus resembling shagreen ; 

 while the hyo- and hypoplastral bones 

 of the lower shell are united ; and there 

 is a flap of skin on each side of the under 

 surface, beneath which the hind-limbs 

 can be concealed. All the forms are 

 confined to the Old World ; and while 

 one of the three genera is Indian, the other two are African. The Indian genus 

 Emyda is readily characterised by the presence of a complete series of neural 

 bones in the carapace, coupled with a semicircle of marginal bones at its hinder 

 extremity. In neither of the three living species does the length of the shell and 

 its soft disc exceed 10 inches, but much larger fossil forms are found in the 

 Pliocene rocks of India. Both the African genera lack marginal bones, but whereas 

 in one (Cycloderma) there is a full series of neural bones to the carapace, in 

 the other (Cyclanorbis) these form an incomplete and interrupted series. 



All the soft-tortoises are thoroughly aquatic, most of them but 

 rarely leaving the water except for the purpose of laying their eggs, 

 and in consequence of these habits very little is known as to their mode of life. 

 Although confined as a rule to rivers, a few of the species frequent estuaries, and 

 Cantor's soft-tortoise has been found some distance out at sea. Occasionally, 

 again, specimens of the Indian granulated soft-tortoises have been met with 

 wandering on land far from the neighbourhood of water. Fiercer and more 

 spiteful than any other members of the Chelonian order, these tortoises, owing to 

 a peculiarity in the structure and mode of articulation of some of the vertebras of 

 the neck, have the power of darting out the head with inconceivable rapidity, 

 the great Indian chitra being facile princeps in this respect. Owing to this habit 

 the larger species are dangerous creatures to approach incautiously, as their bite 



SOFT-TORTOISE. 



Habits. 



