THE LIZARD 



6^)6 



T, Ao 



stools, fruits, and other vegetable nratter. Water turtles eat 

 worms, insects, frogs, and fishes. Some sea-turtles, Hke our 

 green turtle, eat various algae; others, hke the tortoise-shell 

 turtle, are carnivorous, living on fish and moUusks. The jaws 

 are toothless, but are provided with a sharp cutting edge. The 

 stomach and intestines are 

 simple. The cloaca is large. 



Organs of circulation. — The 

 general features of the circula- 

 tion are similar to those for 

 birds described in the next 

 chapter. But the heart, while 

 showing an advance over am- 

 phibians, is far from showing 

 the perfection of development 

 found in birds and mammals. 

 Venous blood from the body is 

 received by the right auricle 

 and poured into the ventricle. 

 The ventricle is incompletely 

 divided into a right and a left 

 chamber by a perforated par- 

 tition (Fig. 332, a). When the 

 auricles contract, the blood 

 from the right auricle passes to the right side of the 

 ventricle, called the pulmonary space (Cp), and the Ijlood 

 from the left auricle (pure and bright because having just come 

 from the lungs) fills the rest of the ventricle. When the ven- 

 tricle contracts, the imperfect partition (a), cutting off the 

 pulmonary space, becomes drawn tight across the ventricle. 

 The blood in the pulmonary space goes to the lungs to become 



2a 



Fig. .3.32. — Di;igrani of the heart of a 

 turtle. SyHteniio Ijlood from the 

 right aurieh' {R.A), passes by the 

 course, x, through the opening at y 

 in the incomplete septum, a, into the 

 chamber, Cp ; thence, on contraction 

 of the ventricle to the pulmonary 

 ^artery (P. A) by the path £. Blood 

 from thi' liuigs passes from the left 

 auricle (L.A) through the passage ^o 

 (guarded by the ^'alve, v), into the 

 larger chamber of the ventricle. On 

 contraction, the opening y being 

 automatically closed, the blood goes 

 b3^ .s- and I to the left and right 

 aortas, respcctiveb', and so on to 

 the bodj'. .^fter Hu.xley. 



