834 THE NERVOUS SYSTEM OF THE OX 
The following paired plexuses are derived mainly from branches of the eceliae 
and aortic plexuses: 
1. The renal plexuses (P. renales) proceed largely from the cceliaco-mesenterie 
ganglia, but receive fibers also from the small splanchnic nerves. They enlace the 
renal arteries and supply the kidneys. Minute renal ganglia occur on the course 
of the nerves along the renal vessels. 
2. The adrenal plexuses (P. suprarenales) are formed by a relatively very 
large number of fine fibers derived in great part directly from the cceliaco-mesen- 
teric ganglia. Numerous minute ganglia occur in their meshes. 
3a. The spermatic plexuses (P. spermatici) proceed from the aortic plexus 
and branches from the posterior mesenteric ganglion. Each accompanies the 
corresponding (internal) spermatic artery to the testicle. 
3b. The utero-ovarian plexuses (P. ovarici) are the homologues in the female 
of the preceding. They accompany the utero-ovarian arteries to the ovary and the 
cornua of the uterus. 
The pelvic plexuses (P. hypogastrici) are the pelvic continuations of the aortic 
and posterior mesenteric plexuses.. Two or more nerves proceed from the posterior 
mesenteric ganglion and enter the pelvic cavity ventral to the large vessels, anasto- 
mose with each other and with branches from the sacral nerves—especially the 
third and fourth—and ramify on the pelvic viscera. The peripheral plexuses 
derived therefrom are named according to the organs which they supply; the chief 
of these are the hemorrhoidal, vesical, utero-vaginal, prostatic, cavernous (of the 
penis or clitoris) (P. hemorrhoidalis, vesicalis, uterovaginalis, cavernosus penis s. 
clitoridis, ete.). Others enlace the arteries (P. iliacus, femoralis, etc.). 
THE NERVOUS SYSTEM OF THE OX! 
The spinal cord resembles that of the horse in conformation and structure. 
In cattle of medium size its length is about 165 to 170 em. (ca. 65-67 inches), and 
its weight about 240 to 250 grams (ca. 8 ounces). 
In a cow 140 em. in height Dexler found the weight of the cord (including the intradural 
nerve-roots) to be 260 gm. and the length 162 em. The lengths of the regions were: cervical 41 
em., thoracic 72 em., lumbar 32 cm., sacral 7 cm. 
The brain has an average weight of about 500 grams (ca. 16-17 ounces). 
Its differences in general form are correlated with those noted in the consideration 
of the cranial cavity. 
The medulla oblongata is short, wide, and thick. Its ventral face is strongly 
convex. The pyramids are narrow, short, and close together in front. Near the 
decussation there is a well-defined oval prominence on either side which indicates 
the position of the posterior olive. The corpus trapezoideum is large; it has no 
central part between the pyramids. The external arcuate fibers are distinct. The 
restiform bodies are short and thick and diverge more strongly than in the horse. 
The floor of the fourth ventricle is only about two-thirds as long as in the horse. 
The area acustica is a well-marked oval prominence lateral to the middle part of 
the limiting sulcus. The tuberculum acusticum at the origin of the acoustic nerve 
is very large. The anterior fovea is distinct. The posterior recess of the fourth 
ventricle communicates through a median aperture (Apertura mediana)? with the 
subarachnoid space. 
1 Only the most salient differences as compared with the horse will be mentioned. 
2 Also known as the foramen of Magendie. 
