THE FROG 33 



(rf) Esophageal. This artery arises from the systemic 



arch posterior to the subclavian, about half way 



between it and the dorsal aorta. As a rule it comes 



only from the arch of the left side. 

 (e) Dorsal Aorta. If the stomach is pulled aside this 



artery will be found along the spinal column; it is 



formed by the union of the systemic arches of the 



right and left sides. 



Branching from the dorsal aorta are : 



(I) Coeliaco-mesenteric. This large artery extending 

 to stomach, intestine, pancreas, liver, and spleen 

 comes from the dorsal aorta just posterior to 

 the union of the two sides of the systemic arch; 

 but the blood is derived almost entirely from the 

 left side of the arch. The coeliac artery supplies 

 the stomach, the mesenteric the intestine, the 

 splenic the spleen. 



(II) Urino-genital and lumbar arteries arise from the 

 ventral side of the dorsal aorta in pairs, and 

 extend to the kidneys, reproductive organs, fat 

 bodies, and dorsal body wall. 



(Ill) Near the extreme posterior end of the dorsal 

 aorta a small posterior mesenteric artery passes 

 into the rectum. 

 (/) Common iliac arteries are formed by the division of 



the dorsal aorta; they supply blood to the hind legs. 



(J) A short distance from its origin each common 

 iliac gives off, on the outer side, one or more 

 epigastric arteries which extend to the ventral 

 abdominal wall. 



(II) Slightly posterior to the epigastric a small artery, 

 the recto-vesical, comes out on the inner side of 

 the iliac and supplies blood to the bladder, cloaca, 

 and pelvic muscles. 



