REPTILTA. 317 



tortoises (tlie genus Trionyx), whicli are occupied by fibro-cartilage ; 

 iu the laud-tortoises, on the other hand, and in the genus Emys, the 

 nine pieces of the sternum are mutually luiited by sutui-e in the 

 adult period without interposed cartilage. The tortoises are tenacious 

 of life, and exhibit a long persistence of irritability in parts that 

 have been divided from the body. They attain a great age '. Most 

 of them live on vegetable food, or on molluscs also. Dming the 

 pairing season the tortoises, at other times usually timorous and 

 dull, are uncommonly lively and courageous. When copulating, 

 which is a work of days, the male is carried on the back of the 

 female. The females lay their eggs on the land, although copula- 

 tion, in the species that live in water, takes place there; they bury 

 the eggs when laid in the ground, in open places exposed to the 

 smij those that live in water do this at such a distance from the 

 shore of the sea, or from the bank of rivers, that the highest state 

 of the water cannot reach them. The nmnber of eggs is various; 

 the land-tortoises lay the smallest number, four or five, some species 

 however more, twelve or twenty; the fresh-water tortoises more; 

 the sea-tortoises the greatest number; commonly a hundred, or 

 even more. 



Compare J. G. Schneider, Allgemeine Naturgeschichte der ScJiildhroten, 

 Leipzig, 1783, 8vo; — J. D. Sch(Epfp Historia testudinum iconibus illus- 

 trata, Erlangse, 1792, 4to; accurate figures and descriptions distinguish 

 this work, which is unfinished (32 col. plates, 132 pp.); — T. Bell, A 

 Monograph of the Testudinata, London, 4to (this work, commenced in 

 1826, contains very beautiful coloured figures; it is still incomplete. I 

 have seen 34 plates of it); — L. JTitzinger Entwurf einer systematischen 

 Anordnung der Schildkroten, Ann. des Wiener Museums, i. 1835, s. 103 — 

 128. (A. F. Schweiggee Prodromus Monographice Cheloniorum, Eegio- 

 monti, 18 14, is known to me only from quotations.) A. Dumeril Dcsaip- 

 tion des Reptiles du Museum. Cheloniens. Archives du Mus. d'JIist. nat. 

 VI. 1852, pp. 212 — 249. 



The work of BOJANUS already noticed (p. 211) is the chief work for the 

 anatomy. 



A. Toes distinct. Feet ^palmate. 



Trionyx Geoffr. {Gymnojyus and Cryptopus DuM. and BiBR.). 

 Covering of beak horny. Lips distinct, soft. Nose proboscidian. 



1 Two examples are adduced of tortoises that continued alive more than a century 

 in a garden in England; J. G. SCHNEIDER Sammlung vermischter Abhandlungen. 

 Berlin, 1784, s. 308, 309. 



