216 The Alligator and Its Allies 
leg. After giving off the fibular and tibial arteries, 
the sciatic passes, as a large vessel, through the 
lower leg, to which it gives but few branches, and 
may here be called the crural artery, cr. At the tar- 
sus it divides rather suddenly and, perhaps, vari- 
ably, into four chief branches, leading to the toes. 
A short distance caudad to the origin of the iliacs 
the dorsal aorta gives off a pair of small pelvic arter- 
ies, pat, going to the muscles of that region. Cau- 
dal to these pelvic arteries is given off the unpaired 
first hemorrhoidal artery, het, which divides into a 
rectal, rt, and a cloacal, cl, branch. 
Caudal to the first heemorrhoidal arises the second 
hemorrhoidal, he’; also unpaired, leading to the 
cloaca. 
Posterior to the second hemorrhoidal, the aorta 
continues into the tail as the large caudal artery, ca. 
The Anterior Arteries. The origin of the great ar- 
terial trunks—the pulmonary, aortic arches, primary 
carotid, and right subclavian has already been given 
and the distribution of the pulmonary arteries and 
aortic arches has been described, so that it now re- 
mains to describe the distribution of the right sub- 
clavian, Fig. 62, sc.d., and the primary carotid, capr. 
The right subclavian, sc.d., since it has an 
independent origin from the heart, instead of aris- 
ing as a branch of the primary carotid, will be 
described first. After leaving the heart it passes 
cephalad and laterad and gives off the following 
branches in order, beginning at the heart: an 
