STRUCTURE OF CROCODILES 



715 



The blood driven to the lungs is purified there, and returns by pul- 

 monary veins to the left auricle. Thence it passes through a valved 

 aperture into the left ve utricle. Thence it is driven into the right aortic 



Fig. 424. — Pectoral girdle of crocodile. 



sc, Scapula ; gl.c, glenoid cavity ; co., coracoid ; c.f., coracoid 

 foramen ; i.cl., episternum. 



arch. From this the carotids to the head and the subclavians to the 

 fore-limbs are given off. These parts of the body thus receive wholly 

 arterial blood from the heart. 



The venous blood returning 

 from the posterior regions may 

 pass through the kidneys in a 

 renal-portal system, and thence 

 into the inferior vena cava ; or 

 it may pass through the liver in a 

 hepatic -portal system, and thence 

 by hepatic veins into the inferior 

 vena cava ; or some of it may 

 pass directly into the inferior 

 vena cava. The renal-portal 

 veins arise from a transverse 

 vessel uniting the two branches 

 of the caudal, but the latter are 

 also continued forward as lateral 

 epigastrics which enter the liver. 



The temperature of the blood 

 is not above that of the surround- 

 ing medium. 



In regard to the respiratory system, we should notice that the lungs 

 are invested bv pleural sacs, as is the case in Mammals. 



The ureters of the kidneys, the va-^a deferentia from the testes in the 



Fig. 425. — Half of the pelvic 

 girdle of a young crocodile. 



//., Ilium ; a.f., acetabulum ; Is., 

 ischium ; P., pubis or epipubis. 



