218 The Alligator and Its Allies 
of the shoulder; (b) the thoracic, t', carrying blood 
to the posterior muscles of the shoulder and to the 
posterior region of the upper arm; (c) the brachial, 
br‘, which is really the continuation of the subclav- 
ian and is the chief artery of the anterior appendage. 
After sending several branches to the upper arm 
the brachial divides, in the region of the elbow, 
into two main vessels, the radial, rat, and ulnar, 
ul', arteries, Fig. 62, A. The radial artery, in the 
carpal region, divides in a complicated way into 
five main vessels that extend into the digits. 
The ulnar artery gives off several branches to the 
forearm, but apparently does not connect directly 
with the branches to the digits. 
The primary carotid, capr. After leaving the 
heart, this very large vessel passes cephalad and 
laterad for some distance on the left side of the 
body and then gives off, from its anterior side, the 
large left subclavian artery, sc.s., to be described 
later. After giving off the subclavian artery, it 
makes a short loop, still farther to the left, and then 
turns sharply mediad to pass to the head in the 
median plane directly dorsal to the cesophagus. 
Its distribution in the cervical and cephalic region 
will be described later. The mate to the cesoph- 
ageal branch, oe (near heart), of the right sub- 
clavian which was mentioned above is apparently 
sometimes given off from the primary carotid near 
its base (as shown in Fig. 62) and sometimes as a 
branch of the left pleural artery. 
