THE STOMACH 



395 



wall of the reticulum about five or six inches above the bottom of the latter. It 

 is rounded, and is limited below and laterally by the junction of the lips of the 

 oesophageal groove. 



In the reticulum the mucous membrane is raised into folds about half an inch 

 high, which inclose four-, five-, or six-sided spaces (Cellulffi reticuli) ; this peculiar 

 arrangement suggested the scientific name, and also the popular term "honey- 

 comb." These cells are subdivided by smaller folds, and the bottoms are studded 

 with pointed horny papillae. The cells grow smaller and gradually disappear near 

 the oesophageal groove and the edge of the rumino-reticular fold; an inch or two 

 from the latter the mucous membrane has the papillary arrangement of the rumen. 



Fig. 290. — Riticuh;m of Ox, from Photograph. 

 The specimen was cut along the greater curvature and laid open by reflecting the anterior wall. C, k the 

 cardia. The arrow points to the reticulo-oinasal orifice. The spiral twist of the oesophageal groove was of 

 necessity partly undone by reflecting the wall; its lips are drawn apart, showing some of the peculiar birdclaw-like 

 papillae in the lower part. 



At the reticulo-oinasal orifice there are peculiar horny papillse, which are curved 

 and resemble the claws of a small bird. 



The cavity of the omasum is occupied to a considerable extent by about a 

 hundred longitudinal folds, the laminae (Laminae omasi), which spring from the 

 dorsal and lateral walls. The largest of these-^a dozen or more in number — have 

 a convex attached edge, and a ventral, free, slightly concave edge which reaches 

 to within a short distance of the ventral wall of the sac. If these are drawn apart 

 or a cross-section is made, it will be seen that there is a second order of shorter 

 laminae, and a third order still shorter; finally, there is a series of very low folds 

 or lines. The food is pressed into thin layers in the narrow spaces between the 

 laminae (Kecessus interlaminares), and reduced to a fine .state of division by being 

 ground down by the numerous rounded horny papillae which stud the surfaces of 

 the folds. The ventral wall of the omasum forms a groove (Sulcus omasi), which 



