THE NERVOUS SYSTEM OF THE PIG $43 
related to the anterior mesenteric artery. The two are connected by gangliated 
cords, and are similarly connected with the ganglia of the opposite side, so that the 
arrangement is plexiform. The celiac plexus is more complex than that of the 
horse in correlation with the compound character of the stomach. The posterior 
mesenteric ganglion is small and is situated behind the artery of like name. It 
receives fibers from the last three or four lumbar ganglia and two fasciculi from the 
anterior mesenteric ganglia. The pelvic viscera receive branches from the posterior 
mesenteric ganglion and from the 
sacral gangla; the latter number 
five pairs, and the right and left 
trunks are connected here by trans- 
verse anastomoses. The coccygeal 
trunks unite at a single fourth coc- 
cygeal ganglion, then separate, and 
reunite at the sixth coceygeal gan- 
glion. 
Longitudinal fissure Frontal pole 
THE NERVOUS SYSTEM OF 
THE PIG 
The spinal cord weighs about 
one and a half ounces (ca. 42 gm.). 
It is almost circular in cross-section, 
except at the enlargements, where 
it is somewhat flattened dorso-ven- 
trally. The conus medullaris ex- 
tends to the anterior part of the 
third sacral segment. The epidural 
space is occupied by a large quan- 
tity of fat. 
The brain in adults of medium 
size weighs about four to four and 
a half ounces (ca. 125 gm.). When at? 
viewed from above, the cerebrum as oblongata 
has an elongated oval form. The 
hemispheres are widest at the pos- Fic. 671.—Brary oF Pic; Dorsat View. 
terior third. The occipital pole is MESURE Zh Lateral, 2, Spee, reali anterior (2’) 
larger than the frontal pole. The ie yiiae af pecrgaayt Kahera ie 3 ae (es 
vian; 6, marginal; 7, ectomarginal; 8, entomarginal; 9, cruciate. 
medulla oblongata is relatively Two different arrangements of the coronal and cruciate fissures 
broad. The cuneate tubercle is very 27 Se oF the two sides. 
large and is limited laterally by a 
groove. The corpus trapezoideum is very wide laterally. The pons is less promi- 
nent than in the ox. The cerebellum is very wide and short. Its anterior face is 
flattened and presents a depression for the corpora quadrigemina. The vermis is 
large. The hemispheres consist of a large medial part and a small lateral part. 
The cerebral peduncles are very short. The posterior corpora quadrigemina are 
wide apart, rounded, and relatively large. The medial geniculate body is promi- 
nent. The cerebral hemispheres are somewhat bean-shaped in lateral profile, the 
convex border being dorsal. The arrangement of the gyri and sulci is simpler than 
in the horse or ox. 
Cerebellum 
The principal fissures are as follows: ech 
1. The lateral fissure (of Sylvius) begins at the sulcus rhinalis and runs upward and 
somewhat backward on the depressed part of the lateral surface of the hemisphere; it appears 
