472 DIGESTIVE SYSTEM OF THE SHEEP 
does not project into the isthmus fauctum. The mucous membrane of the latter 
presents two deep and very narrow tonsillar sinuses on either side. 
The fornix of the pharynx presents a median plicated fold which is a continua- 
tion of the septum nasi. The pharyngeal orifice of the Eustachian tube has the 
form of a crescentic slit, placed about on a level with the ventral nasal meatus. 
There are two large lymph glands and a number of hemolymph glands above the 
pharynx. 
The cesophagus has a lumen of about an inch (ca. 2.5 em.) when moderately 
distended; otherwise it resembles that of the ox. 
The stomach is like that of the ox in its general arrangement. Its average 
capacity is about four gallons (ca. 15 liters). The cardia is opposite the eighth 
intercostal space; it is just to the left of the median plane, and about two inches 
_ Dorsal curvature of 
rumen 
Posterior 
groove of 
rumen 
Fig. 405.—Sromacu or SHeep; Lerr View. 
From photograph of specimen hardened in situ. The reticulum is somewhat contracted. 
(ea. 5 em.) below the vertebral column. The dorsal sac of the rumen is a little longer 
than the ventral sac and extends considerably (ca. 7.8 cm.) further forward than 
the latter. The ventral sac is relatively larger and extends further to the right of 
the median plane than in the ox; its posterior blind sac extends further (ca. 6-8 em.) 
back than that of the dorsal sac. The parietal attachment of the dorsal sac 
extends back to the second lumbar vertebra. The left longitudinal groove ex- 
tends upward and backward for a short distance only, and therefore does not 
connect with the posterior groove. There are two longitudinal grooves on the 
right side which join at each end, thus enclosing a long, narrow prominent area; 
the dorsal one contains the right ruminal artery, and the ventral one corresponds to 
