TESTUDINIDAE 365 



portion of the plastron is strongly forked in front, and projects 

 l)eyond the anterior Ijorder of the carapace. This peculiar 

 creature reaches a length of nine inches. When withdrawn 

 within the shell, which is closed behind and depressed in front, 

 with the jagged edges of the plastron and the anterior marginals 

 protecting the drawn-in head, it has a very quaint appearance. 

 It lives entirely on fruit and other vegetable matter, and is said 

 to prefer to lie in the water, while C. helliana is supposed to be 

 entirely terrestrial. 



Fig. S2. - Civyxis erosa. x h- 



Pyxis arachnoidcs, of Madagascar, a small land-tortoise, only 

 four inches in length, has an immovable carapace, but the front 

 lobe of the plastron is hinged, 



Teshido. — The plastron is immovable, except that in old indi- 

 viduals of some species, e.g. T. ihera, the hinder lobe develops a 

 transverse flexible hinge. They have existed since the Oligocene 

 of North America and Europe ; and are now represented by nearly 

 forty species in all the tropical and warmer temperate countries 

 excepting the Austro-Malayan and Australian region. Typically 

 terrestrial, herbivorous and frugivorous, although occasionally 

 varying their diet with worms, molluscs, and insects. The eggs 

 are hard-shelled, mostly less oval than those of the aquatic and 

 semi-aquatic tortoises. The males generally remain smaller than 

 the females, have a slightly longer tail, and have a concave 

 instead of a flat plastron. Most land-tortoises hibernate in the 

 ground during the cool and cold seasons, or they aestivate during 

 the hot and dry months of tropical countries, luit this is not an 

 invariable rule. 



T. graeca, the common " Greek Tortoise." The shell is very 

 convex, without keels, and has a smooth, not serrated margin. 



