TSE 8T0MACS. 



399 



Slruciure. — ^The serotis layer is a dependency of tlie peritoneum, and offers nothing 

 particular ; it does not completely cover the anterior face. 



The muscular tunic is much fasciculated, and thin. 



The mucous membrane is remarkable for the thickness of its stratified pavement 

 epithelium ; all the leaves are formed by two layers of this membrane, laid one against the 

 other ; and as their structure is interesting, we will notice it. 



The principal leaves are composed of this duplioatme of mucous membrane, and two 

 layers of muscular fibres between ; these layers are opposite each other at the commence- 

 ment of the leaf, and separated by a transverse vessel ; in the remainder of their extent 

 they are kept apart by the vessels that pass towards the border of the leaf. Their fibre s 

 are detached from the surface of the muscular tunic and, at certain points, from its deep 

 layer. In the smaller leaves there appears to be only one layer of muscular fibres ; on 

 all the leaves are Tarious-sized papillae, the smallest of which are like a grain of millet. 



Fi?. 195. 



Fig. 196. 



T — 



SECTION OF A LEAF OP THE OMASOM. LONGITHDISAL SECTION OF A LAEftE PA- 



1, 1, Muscular planes ;«, vessel; 2, Epithe- wlla peom the omasum, showing 



lium; 3, 3, Small-sized papillae, round NERVE-CELLS IN ITS INTERIOR, 



and hard. 



and have for base a mass of condensed connective tissue, whose superficial fibres form a 

 kind of shell (Fig. 195) ; the largest are club-shaped. They receive blood-vessels, and 

 we have found in the connective tissue, elements with a somewhat irregular outhne. pro- 

 vided with nuclei, which we considered to be nerve-cells (Fig. 196.) 



A.BOMASTJM (Reed or Een-net. Figs. 192, ld3).Situation—Form—HeUtions.~lhe 

 abomasum stands next to the rumen for capacity. It is a pyriform reservoir, curved on 

 itself elongated from before to behind, and situated behind the omasum, above the right 

 sac of the rumen On the right it touches the diaphragm and the hypochondriac; on 

 the left it is related to the rumen. The greater curvature, turned downwards, receives 

 the insertion of the great omentum. The lesser curvature, inclined upwards gives 

 attechment to the serous band already noticed when speaking of the great curvature of 

 the omasum Its 6ase is in contact with the cul-de-sac of the reticulum, and is separated 

 fromThe omasum by the constriction in the form of a thick neck, which corresponds to 

 The commuStag orifice of the two stoma.3hs. Its point, directed upwards and back- 

 wards lij continued bv the duodenum. i. v • 



iferr-This being the true stomach of Ruminants, the mucous membrane lining 

 its inter OT acquires all the characters which distinguish that of the stomach of the 

 Its interior acquires a Horse's stomach. It is soft, spongy, smooth to 



fhTtrh valclr red"°ob^^^^^ by a thin epithelium, and provided with 



the toucb, ™scmar, re ^ ^ j j j^j^e. Thinner than m monogastno 



numerous glands for the jcret^^^ ^^^^^ ^^^^^^^ ^^ surface, which is 



^tTfurth^ii^^reieVl^^^^^^^^ lamellar folds. These latter are analogous m eon- 

 stitntion to hose of thJ omasum, cross in a very oblique manner the great axis of the 

 sntalion ^° "^"-^,. .-u ggct a kind of spiral arrangement. 



abomasum, a°'i,^™f^ftwo a^^^^^ : one, situated at its base, opens into the omasum; 

 tJ^i:^V^o;i^^ZTe first and much narrower, is the pylorus, which is 



^t^cf ^b^d, ^t:^^:^^:,-^^!.. omenta wmeh abut on the 

 Structure.--The serous memo^^ TOMsc«Zar layer is of tlie same thickness 



great and ^^^<'^^'^^^^'Z°J;^altlnie has already been noticed. 



asm the omasum. Jf „"^;'jj, EcminantZ-Wc cannot pretend to give here a 

 ^Tri?-Z^oiTe phenomena" rumination, but must confine ourselve? to describe 



ntw^^s^hL aA pSncipal attributes of each gastric dilatation. 



