XXIII] 



CROCODILIA 



601 



5 



root of the aorta arises from the right ventricle and crosses the 

 right root, which arises from the left ventricle and gives off the 

 two carotids. The left root therefore receives venous blood from 

 the right auricle and 

 the blood sent to the 

 trunk is mixed. In ad- 

 dition there is a small 

 passage, the foramen 

 of Panizza, joining the 

 two trunks where they 

 cross, so that the blood 

 leaving the right arch to 

 go to the carotid is also 

 somewhat mixed. The 

 right common or dorsal 

 carotid is very reduced, 

 the left-hand vessel 

 supplying both sides of 

 the head (Fig. 301). 

 The fore-limb receives 

 blood by a subclavian of 

 the ventral type, as in 

 Chelonians. The lung 

 is no longer a simple sac, 

 but has thick spongy 

 walls and the central 

 passage is reduced to a 

 najrow tube. In the 

 brain the cerebellum 

 is large and cylindrical. 

 All these peculiari- 



HVe nf f>io infor-nol 

 Organs' may be termed 



foreshadowingS of what 



/, -, . -o' i 

 is found in Birds and 



Mammals, and hence 



Crocodiles are styled 



rightly the highest of living Reptiles. 



Crocodiles are inhabitants of rivers and swamps and spend most 

 of their life in the water. The best known and classical example is 

 the Crocodile of the Nile, Crocodilus niloticus. There is but one 



299. Sternum and associated membrane 

 bones of a Crocodile, G. palustris x $ . 

 The last pair of abdominal ribs which are united 

 witl1 the epipubes by a plate of cartilage have 

 been omitted. 



^ Interclavicle . 2 . sternum . 3 . Sternal 

 rib. 4. Abdominal splint rib. 5. Sternal 



band ' 



