The Frog 



59 



The blood from the lungs empties into the left auricle by two small 

 veins, one from each lung. 



THE ARTERIES 



Blood vessels pass to every part of the body. We know they are 

 everywhere because one cannot insert the point of the finest needle in 

 any part of the body without piercing them, showing they are so close 



External 



Syshmic.a. ^ Mmocuk 



J (aortic) s ^ 

 Occipital^a. 



Cutaneous a 



Sub- 

 clavian 

 artery 



Pulmonar 



_ carohd 'Occipital <X. 

 eous j S gland/ 



Internal carotid 



Common carotid a. 



Occwito -vertebral 

 ^ artery 



Vertebral 

 artery 



Coeliaco -mesenteric artery 

 Dorsal aorld 



Spermatic- a. , 

 Testis '' 



Liver 



rjL -Hepatic a. 



-Coeliac a, 

 ~" - * Stomach 



^Common 

 w gastric a. 

 ^ -Jinterior 

 mesenteric a. 



- — -Intestine 



Iliac 

 artery 



% ' arteries 



Fig. 13. The Arterial System of the Frog. 

 (Redrawn from Meissner.) 



together that one cannot get in between them. Arteries are always 

 relatively thicker- walled and more elastic than veins (Fig. 12). 



The principal divisions of the arterial system (Fig. 13) may be 

 summarized as follows : 



