444 



DIGESTIVE SYSTEM OF THE OX 



the csRcum 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 hgament 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, 386). 



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 (Glandulse nasolabi- 

 ales); they form a subcutaneous layer about 

 half an inch (ca. 1.5 cm.) 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 papillae ; toward the angles the papillae 

 become longer and sharp-pointed. The labial 

 glands occur only near the angles, where they 

 form compact masses (Fig. 385). 



The cheeks are more capacious than in 

 the horse. The mucous membrane presents 



Fig. 379. — Lipa and Muzzle of Ox. 



1, Muzzle: 2, nostril; 3, 4, wings of nos- 

 tril; 5, 6, commissures of nostril; 7, S, upper 

 and lower lip. 



