THE FROG 37 



(&) Branches of the dorsal aorta. 



The cceliaco-mesenteric artery is a large artery arising 

 near the junction of the systemic arches; it divides into the 

 cceliac and the anterior mesenteric arteries. The cceliac 

 artery gives off the left gastric artery and finally divides 

 into the hepatic and right gastric arteries; trace their dis- 

 tribution. The anterior mesenteric artery sends branches 

 to the spleen (splenic artery) and small and large intestines. 



The urogenital arteries are four or five (or even more) 

 small arteries which arise from the ventral surface of the 

 dorsal aorta and supply the kidneys, fat-bodies, sexual organs 

 and the ducts of the urogenital system. Those arteries that 

 are distributed to the kidneys alone are sometimes called 

 renal arteries. 



The lumbar arteries are small vessels, variable in number 

 and position, passing to the neighboring dorsal body wall 

 and to the spinal cord. 



The posterior or inferior mesenteric is a slender artery 

 arising from the ventral surface of the dorsal aorta near its 

 posterior end. It supplies the posterior portion of the rec- 

 tum, and in the female sends branches to the uteri. 



The large iliac arteries are produced by the bifurcation of 

 the dorsal aorta. A short distance behind the bifurcation 

 each artery gives off a branch, the epigastrico-vesicalis, 

 which divides into an epigastric artery supplying the ven- 

 tral body wall, and a recto-vesical to the rectum and blad- 

 der. Further on the iliac artery gives off the femoral 

 artery to the muscles and skin of the hip region; it then con- 

 tinues down the thigh as the sciatic artery. The iliac artery 

 and its branches can be studied from the body cavity. To 

 expose the sciatic artery proceed as follows : Mark the point 



