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 longitudinal 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 cesophageal 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 csophageal 
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 cesophagus. 
The external muscular layer of the aesophagus is in part continued 
down along the cesophageal groove (7. 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 cesopha- 
geal groove; part of it is continuous with 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 lamine contain three muscular 
strata. The fibers of the central layer extend from the at- 
Me. 394.—Mvscvura- tached edge toward the free edge, but do not reach the latter; 
TURE OF CisOPHAGEAL 7 
GROOVE AND ADJACENT 
Parr or SToMacH oF 
Ox, SEEN FROM WITHIN 
AFTER REMOVAL OF 
Mucous MEMBRANE. 
Dorsal sac 
a, (Xsophagus; }, in- Rumen Gesophagas 
ner muscular layer of atri- 
um; d, reticulo-omasal ori- ioe Parigre) is 
fice; e, e’, muscle of lips of blind sacs 
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; Ah, lower 
end of muscle of smaller 
lip, which in part curves Abomasum 
around the reticulo-omasal 
orifice and is in part con- 
tinuous with the inner mus- 
cular layer of the omasal 
groove and the omasum; 
7, inner muscular layer of 
reticulum. (Ellenberger- Fic. 3§ 
Baum, Anat. d. Haustiere.) The rumen is raised. 
5—Sromacu or NEW-BORN Car; Ricut View. 
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 mucos:e. 
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 
