462 



DIGESTIVE SYSTEM OF THE OX 



much thicker and its fibers have the same direction as the pillars. Thus the muscular tissue of 

 the pillars is seen on cross-section to consist of two thick layers of longitudmal fibers, which are 

 separated (except at the free margin of the pillar) by a thin axial layer of fibers disposed at right 

 angles to the preceding. 



The muscular coat of the reticulum consists of two chief layers which begin 

 and end at the oesophageal groove; they pass in a circular or oblique fashion around 

 the sac, the fibers of the two layers crossing each other at varying angles. The 

 walls of the cells contain a central muscular layer. The lips of the oesophageal 

 groove consist chiefly of a thick layer of longitudinal fibers, which are largely con- 

 tinuous at, or cross each other below, the reticulo-omasal orifice. The bottom of 

 the groove has two layers of oblique, unstriped muscle-fibers, 

 with a variable outer layer of striped muscle continuous with 

 that of the oesophagus. 



The external muscular layer of the cesophagus is in part continued 

 down along the oesophageal groove (i. e., along the lesser curvature of 

 the reticulum), but in greater part spreads out on the wall of the rumen 

 and reticulum. The internal muscular layer of the cesophagus forms a 

 loop over the cardia and is largely continued in the lips of the oasopha- 

 geal groove; part of it is continuous wth the muscular layer of the 

 bottom of the groove. 



The muscular coat of the omasum consists of a thin ex- 

 ternal longitudinal layer and a thick internal circular layer. 

 At the omasal groove there is an incomplete inner layer of 

 oblique fibers. The larger laminse contain three muscular 

 strata. The fibers of the central layer extend from the at- 

 tached edge toward the free edge, but do not reach the latter; 



Fig. 394. — Mttscula- 

 tuke of cesophageal 

 Groove and Adjacent 

 Part of Stomach of 



Ox, SEEN FROM WITHIN 



AFTER Removal of 

 ^Mucors Membrane. 

 a, CEsophagus; h, in- 

 ner muscular layer of atri- 

 um; d, reticulo-omasal ori- 

 fice; e, e' , muscle of lips of 

 groove; g, lower end of 

 muscle of larger lip, which 

 curves around the reticulo- 

 omasal orifice in part and 

 spreads out in the inner 

 muscular layer of the retic- 

 ulum in part; h, lower 

 end of muscle of smaller 

 lip, which in part curves 

 around the reticulo-omasal 

 orifice and is in part con- 

 tinuous with the inner mus- 

 cular layer of the omasal 

 groove and the omasum; 

 i, inner muscular layer of 

 reticulum. (Ellenberger- 

 Baum, Anat. d. Haustiere.) 



Oesophagus 



Fig. 395 



-Stomach of New-born Calf; Right View. 

 The rumen is raised. 



here there is a marginal band of longitudinal fibers. The central layer is contin- 

 uous with the inner circular layer of the wall. On either side there is a layer of 

 longitudinal fibers, which are continuous at the attached border with the muscu- 

 laris mucosae. 



The muscular coat of the abomasum consists of longitudinal and circular 

 layers; the latter forms a well-developed pyloric sphincter. 



The mucous membrane of the first three divisions is destitute of glands, and 

 is covered with a thick, stratified, squamous epithelium; the superficial part of 



