444 DIGESTIVE SYSTEM OF THE OX 
the cecum and the terminal part of the great colon. From these it passes on the 
right to the duodenum, forming the third part of the mesoduodenum. On the left 
it covers part of the ventral surface and the lateral border of the left kidney, from 
which it passes to the base of the spleen, forming the ventral layer of the suspen- 
sory ligament of the latter. Behind the terminal part of the great colon it is reflected 
from the abdominal wall around the great mesenteric artery to form the great 
mesentery. Behind this it is reflected almost transversely from the roof of the 
cavity and from the origin of the small colon on to the duodenum, forming the 
terminal part of the mesoduodenum. The line of origin of the colic mesentery 
begins on the medial part of the ventral surface of the left kidney, and extends to 
the sacral promontory, where the mesorectum begins. At the termination of the 
latter the peritoneum is reflected from the rectum on to the dorsal and lateral walls 
of the pelvic cavity. Below the rectum it forms the genital fold, and passes on to 
the dorsal surface of the bladder, covers its anterior part, and is reflected on to the 
body-wall laterally and ventrally, forming the lateral and middle ligaments of the 
bladder. In the female the broad ligaments of the uterus replace the genital fold, 
with which they are homologous. 
In the new-born foal certain folds are specially large. The falciform ligament 
of the liver extends to the umbilical opening, and contains in its free edge the large 
umbilical vein. The bladder—at this time an abdominal organ—has a ventral 
median fold (Plica umbilicalis media), which connects it and the urachus with the 
abdominal floor. This is flanked on either side by a fold (Plica umbilicalis lateralis), 
which also extends to the umbilicus, and contains the large umbilical artery. 
DIGESTIVE SYSTEM OF THE OX 
THE MOUTH 
The cavity of the mouth is shorter and wider than that of the horse, and the 
vestibule is more capacious (Figs. 381, 586). 
The lips are thick, wide, and comparatively immobile. The middle part of 
the upper lip and the surface between the nos- 
trils is bare, and is termed the muzzle (Planum 
nasolabiale). It is smooth, and (in health) is 
kept cool and moist by a clear fluid secreted 
by the naso-labial glands (Glandul nasolabi- 
ales); they form a subcutaneous layer about 
half an inch (ea. 1.5 em.) thick. It shows ir- 
regular lines, mapping out small polygonal areas 
on which the orifices of the gland ducts are visi- 
ble. There is also a narrow bare strip along 
the edge of the lower lip. The remainder of 
the integument is provided with ordinary and 
tactile hairs. The free edge and the adjacent 
part of the lining membrane bear short, blunt, 
horny papilla; toward the angles the papille 
y become longer and sharp-pointed. The labial 
Fic. 379.—Lrs anp Mvzzux or Ox. glands occur only near the angles, where they 
1, Muzzle; 2, nostril; 3, 4, wings of nos- form compact masses (Fig. 385). 
tril; 5, 6, commissures of nostril; 7, 8, upper The cheeks are more capacious than in 
and lower lip. 
the horse. The mucous membrane presents 
