CLASS REPTILIA. 



and raising alternately the hyoid bone. The first 

 movement lets the air enter by the nostrils ; and 

 the tongue then closing their interior aperture, the 

 second motion forces this air to penetrate into the 

 lungs. 



The tortoises have no teeth : their jaws are clothed 

 with horn, like those of birds, except in the chelydes, 

 where they are only furnished with skin. Their 

 tympanic cavity, and palatine arches, are fixed to 

 the cranium, and immoveable. Their tongue is 

 short and bristly, with fleshy threads. Their sto- 

 mach is simple, and strong. Their intestines of 

 moderate length, and without coecum, and they have 

 a very large bladder. 



The male has a simple and considerable penis. 

 The female produces eggs covered with a hard shell. 

 The male may often be recognised by its external 

 appearance, because the plastron is concave. 



The tortoises possess amazing tenacity of life. 

 Some have been known to move without a head for 

 many weeks. Very little nourishment is necessary 

 for them ; and they can pass entire months, and 

 even years, without eating. 



The Chelonians, all united by Linnaeus in the 

 genus 



Tortoise. Testudo. L. 



Have been divided into five subgenera, principally, 

 according to the forms and teguments of their cara- 

 paces, and their feet. 



