170 ELEMENTAKY BIOLOGY. [XIII. 



The principal vessels of ' the Frog are disposed as fol- 

 lows : 



A. Arteries. 



1. The system of the anterior aortic arch (carotid 

 trunk). 



a. Lingual artery to the tongue. 



b. Carotid artery to the interior of the skull and 

 the brain. 



2. The system of the middle aortic arch (aortic trunks). 



a. Vertebral and subclavian to the vertebral co- 

 lumn, and to the fore-limb. (Esophageal to the 

 gullet. 



b. Cceliaco-mesenteric (given off from the left arch, 

 or from the dorsal aorta, at, or beyond, the junc- 

 tion of the two arches). 



a. Codiac to stomach and liver. 



j3. Mesenteric to intestine and spleen. 



c. Branches of the dorsal aorta to the adrenal and 

 renal organs, to the genital organs and to the 

 muscles of the back. 



d. The terminal branches of the dorsal aorta (com- 

 mon iliac); each of these gives off hypogastric 

 arteries to the bladder and walls of the abdomen 

 and is continued as the femoral artery into the 

 leg. 



3. The system of the posterior aortic arch (pulmo- 

 cutaneous trunk). 



a. Pulmonary artery to the lungs. 



b. Cutaneous artery to the dorsal integument. 



