EMYS. 21 



EMYS. 



(POND TORTOISES. TERRAPENS.) 



Emys, (Bronr/niart) Cuv. Rec/ne Anim. ed. 1817, p. 10. 



Thorax and sternum solid, entirely bony, and united Into an immoveable 

 earapace in the adult state. The upper shell more or less depressed ; the 

 third and fourth vertebral plates united by a broad suture ; sternum flat in 

 both sexes ; pectoral plates subquadrangular, forming a suture together. 

 Feet with the toes broadly webbed. Claws strong, five anteriorly and four 

 posteriorly. 



This genus is extremely rich in species, inhabiting all the temperate and tropical regions, 

 except Australia. Formerly (between the latest geological and the historical periods) the 

 genus had even a still greater geographical range than now, a species in a semi-fossil 

 state being found in England * and in other European countries, where it is extinct at 

 present. The species undergo great changes in external appearance with age, and it is 

 almost impossible to make out the whole history of the development of a species from the 

 isolated examples preserved in European collections ; on the other hand, naturalists residing 

 between the tropics frequently apply names to species for which they were never intended, 

 thereby rendering their observations on the habits, development, 'and geographical range 

 useless, or productive of numerous errors. Thus the history of the Indian Terrapens, in its 

 present state, is by no means satisfactory, beyond the zoological distinction of the species, 

 which is chiefly due to Dr. J. E. Gray. 



The Terrapens cannot well exist without water ; they abound in still waters and tanks in 

 the lower parts of India ; perfectly motionless, they rest on the water, with the shell and the 

 snout raised above its surface, suddenly disappearing at the approach of danger, and darting 

 away with the swiftness of a fish. Their pointed claws enable them to crawl easily over 

 slippery and steep places, and to dig little holes for a small number of elongate-o^'ate, hard- 

 shelled eggs, which in some species require as long a period as from eighteen to twenty months 

 before they are hatched. They are chiefly carnivorous, and the flatter the shell, the broader 

 the interdigital web, the more denticulated the jaws — the more aquatic and carnivorous are 

 the habits of the Pond Tortoises. The food of the carnivorous species consists of water-insects, 

 frogs, small fishes, small aquatic birds and mammals; whilst on the other hand they are 

 persecuted by alligators and large fishes, and the young and eggs by numerous other animals. 

 They are not used as food by man, the flesh of most species having a very disagreeable smell, 

 which is also perceptible when first taken out of the water in a net or by a hook baited 

 with meat. 



* Emys lutaria. See Newton, Ann. & iMag. Nat. Hist. 1862. 



