236 



HITCHCOCK'S ANATOMY 



ad 



— vp 



og 



nished with the former, but in adult age, after passing through 

 a metamorphosis, have the latter system of respiratory vessels. 



418. Heart of Crocodile. 



— Crocodiles and turtles ex- 

 hibit the most perfect form of 

 heart, for it agrees essentially 

 with that of mammals, as may 

 be seen in Figs 236 and 237. 

 But there is a small opening 

 just at the outlet of the two 

 ventricles, so that the pure 

 and impure blood is mixed. 



419. Portal System. - 

 Keptiles have a double Portal 



System, one set of vessels 

 supplying the kidneys and another the liver. 



420. Lymphatic Hearts. — Many reptiles have small sac- 

 like organs lying just beneath the skin in certain portions of 

 the body, which, from their containing lymph and showing 



Fig. 237. 



i 



^ Pulmonary Artery. 

 *« Pulmonary Vein. 



Heart of Crocodile. % Veins, ao, Eight 

 Auricle, vt. Ventricles, ap. Pulmonary 

 Arteries, a, A Vessel proceeding from the 

 Ventricle to the Aorta. og } Left Auricle. 



Pulmonary Artery. < 



Pulmonary Vein. •* 

 Eight Auricle. 



Vena Cava. - 

 Left Arch of the Aorta. — 



Eight Aorta. 



Left Auricle. 

 Single Ventricle. 



Ventral Aorta. 



Heart of the Turtle. 



pulsations, are called Lymphatic Hearts. In the Frog, two 

 such hearts are situated on 1 

 the joints of the thigh bones. 



such hearts are situated on the back of the animal, between 



418. What animals of this class have the most perfect form of a heart? 419. What kind 

 of a portal system do we find anion;' reptiles? 420 Describe lymphatic hearts. 



