CHELONII. 



which falls off in small pieces. Their lungs are enveloped 

 by the thickened peritoneum, which performs the part and 

 has the appearance of a diaphragm. They are all oviparous, 

 and none of them poisonous ; but some, from their large 

 size and carnivorous habits, are dangerous even to man. 



Order 1. CHELONII, Latr. 



Vertebrae dorsi costse et sternum agglutinata immobilia 

 fornicem dorsalem sternalemque formantia, cute coriacea 

 vel cartilaginea tecta; vertebrae colli 8-9 mobiles; claviculae 

 utrinque duse ; pulmones abdomen intrantes ; os edentulum 

 rostratum; tympana aperta cute tecta; vesica urinaria; 

 penis simplex imperforatus ; anus rotundatus plicatus. 



Linnseus considered the tortoises as forming a genus under 

 the name of Testudo ; Brongniart first separated them as a 

 distinct group under the name of Cheloniens, which has been 

 adopted by Cuvier. Latreille has latinized it to Chelonu ; and 

 Oppel and Merrem use for this group the name of Testudi- 

 nata. 



These animals are peculiar at first sight from their body 

 being included in a bony case {Testa), leaving only the head, 

 neck, limbs, and tail free. These parts are covered with 

 a scaly rugulose or wrinkly skin, and are generally capable 

 of being withdrawn into the cavity of the shell for protection. 

 The head is sometmnes covered with regular shields. 

 The jaws are usually furnished with horny cases, often 

 toothed at the edges in the place of true teeth. The upper 

 one overlaps the other like the lid of a box. They are rarely, 

 as in the genus Chelys, protected with fleshy lips. The 

 tongue is short, blunt, with long filiform papillae. The eyes 

 have distinct eyelids ; and the tympanum of the ear is visible 

 and nearly superficial. The neck varies greatly in length ; 

 it is usually withdrawn into the body of the shell when the 

 animal is at rest, but in those families [Cheli/dce) which 

 have long necks, it is bent on the side of the body under the 

 margin of the shell. The case [lestd) consists of two bony 

 shields {scuta) united by the margin. The upper shield or 

 carapace {scutum dorsale) is formed by the eight pairs of ribs, 

 being more or less dilated on the sides, united together, 

 and adherent to the vertebrae of the back by a toothed seam, 

 so as to prevent their having the slightest motion one on the 



