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 zsch- 
adic@, is*; each ischiadica, after giving off a couple 
of small branches to the back, passes laterad and 
divides into three main branches: (1*) 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 
tliac 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, ft, 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 
