214 The Alligator and Its Allies 



carries blood through the mesentery to the greater 

 part of the small intestine and also sends a small 

 branch to the large intestine. 



Posterior to the mesenteric, the aorta gives off 

 four or five pairs of short arteries, the urogenitals, 

 u 1-4, that lead to the nearby reproductive organs 

 and kidneys. 



About the middle region of the kidneys, a short 

 distance anterior to the sacrum, is given off a pair 

 of rather large arteries, called by Bronn the ischi- 

 adiccB, is"; each ischiadica, after giving off a couple 

 of small branches to the back, passes laterad and 

 divides into three main branches: (i') to the 

 ventral body wall, (3') to the anterior border and 

 deeper region of the thigh, and (2-) to the pelvis. 



In the region of the sacrum is given off a pair of 

 iliac arteries, il'. Each iliac is of about the same 

 diameter as the ischiadica and gives off, soon after 

 leaving the aorta, an artery, ab, that apparently 

 leads chiefly to the abdominal muscles. Distal to 

 the origin of the abdominal, the iliac gives off a 

 small pelvic artery, pa, which leads, as the name 

 would indicate, to the pelvis. The iliac then 

 passes into the thigh, where it gives off several 

 large branches and may be called the sciatic, sc. 

 At the knee the sciatic gives off two rather small 

 branches: one, the fibular artery, f ', extends down 

 along the posterior side of the lower leg ; the other is 

 parallel to the first and may be called the tibial 

 artery, tb, since it extends along the anterior or 



