92 ANTHROPOLOGY. 
of the colon. The sigmord artery is distributed to the sigmoid flexure of 
the colon. The superior hemorrhoidal descends along the back part of the 
rectum, supplies the coats of this intestine, and inosculates with the middle 
and inferior hemorrhoidal arteries. 
5. THE RENAL ARTERIES arise from the sides of the aorta, between the 
superior and inferior mesenteric arteries; both pass behind their correspond- 
ing vein and divide near the kidney Le five or six branches,. which ramify 
through the substance of this gland. 
6. THE CAPSULAR ARTERIES are three in number; they arise either from 
the renal arteries or from the aorta, and supply the poral capsules. 
7. THe SPERMATIC ARTERIES arise from the fore part of the aorta; in 
the male they accompany the vas deferens of each side through the sper- 
matic canal, and supply the testis and epididymis; in the female they pass 
to the ovaries, and also send branches to the Fallopian tubes and to the 
sides of the uterus. 
8. THE LUMBAR ARTERIES are four or five pairs. They are analogous 
to the intercostal arteries, and arise from the back part of the aorta, to be 
distributed mainly to the muscles of the back and loins. 
9. THE MIDDLE SacrAL ARTERY arises from the back part of the aorta, 
a little above its bifurcation; descending nearly in a median line, it sends 
branches to the sacrum and communicates with the lateral sacral arteries, 
This is essentially the continuation of the aorta, as may be clearly seen in 
animals having weak posterior extremities and a highly developed tail. 
Pl. 135, fig. 12", large intestines; *, aorta; °*, superior mesenteric; 
‘section of one of its branches to the small intestines; *, right colic artery; 
*,a vascular arch of the right colic; *, boundary between large and small 
intestines; °, inferior mesenteric; ***”, left colic branch; ™”*, superior 
hemorrhoidal. 
F. Iliac Arteries. 
The right and left common iliac arteries arise and diverge from the 
bifurcation of the aorta, which usually occurs on a level with the lower 
margin of the fourth lumbar vertebra. The point of division, as well as its 
angle, is, however, variable; nevertheless in the female the angle of bifur- 
cation is always greater than in the male. These vessels descend obliquely 
outwards as far as the ilio-sacral symphysis, opposite to which, and resting 
on the psoas magnus, each divides into the external and internal iliac arte- 
ries; their length varies from one and a half to two inches. 
1. THE INTERNAL |zIAc or HypoGastric ARTERY passes downwards 
in front of the ilio-sacral articulation, describing a curve concave forwards, 
and reaches the superior part of sie sacro-sciatic notch, when it panei 
divides into a number of branches. From its termination a ligamentous 
cord (the obliterated umbilical artery of the foetus) extends to the back and 
sides of the bladder, and from this to the posterior surface of the recti 
muscles as far as the umbilicus. It gives off the following branches: ilio- 
lumbar, lateral sacral, hemorrhoidal, vesical, uterine, and vaginal; the 
gluteal, sciatic, obturator, and pudic. 
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