474 DIGESTIVE SYSTEM OF THE SHEEP 
and have serrated edges. The dorsal part of this sac has, in the vicinity of the 
rumino-reticular orifice, a papillated mucous membrane just like that of the 
rumen. The omasum is much smaller than the reticulum, its capacity being 
only about one pint. It is oval and compressed laterally. It is situated almost 
entirely to the right of the median plane, opposite to the ninth and tenth ribs, 
Fic. 407.—CRross-secTION OF SHEEP, THROUGH NINTH THORACIC VERTEBRA; ANTERIOR VIEW. 
1, Cardia; 2, esophageal groove; 8, rumino-reticular orifice; 4, rumino-reticular fold; 5, dorsal sac of rumen; 
6, body of ninth thoracic vertebra; 7, vena hemiazygos; 8, aorta; 9, posterior mediastinal lymph gland; 10, 10, crura 
of diaphragm; 11, posterior vena cava; 12, portal vein; R.l., right lung; L.l., left lung; S, spleen; L, liver; R, reticu- 
lum (posterior wall). Arrow points to reticulo-omasal orifice. The spleen is cut so obliquely as to appear much thicker 
than it really is. 
higher than in the ox, and has no contact with the abdominal wall. It is related 
on the right to the liver and gall-bladder, on the left to the rumen, and ventrally 
to the abomasum. The lamine are less numerous than in the ox; in the neck 
which connects the omasum with the reticulum they have the form of low, thick 
ridges, and bear long, pointed, horny papille. The abomasum is relatively 
