ALIMENTARY CANAL OF ARTIODACTYLA. 467 



of the Peccary, with the exception of the greater length and trans- 

 verse ridges in the middle portion of the cavity. I long ago 

 expected the opportunity of testing and supplementing these 

 descriptions by dissection of the stomach of the full-grown 

 animal : but the Hippopotamus received at the Zoological Gardens 

 in 1850 still lives, in good health (1867), to the credit of that 

 noble and well-administered establishment. 



The stomach of ruminant Artiodactyles is divided into cavities 

 so distinct in boundary, structure, and function, that they have 

 received special names. The first, called f rumen,' or ( paunch,' ' 

 is the largest, forming a capacious reservoir ; its inner surface is 

 commonly villous : that of the second cavity, called ' reticulum,' 2 

 is divided into small compartments or cells, mostly hexagonal in 

 form : the third cavity is occupied by broad longitudinal folds, 

 like the leaves of a book, whence the name ' psalterium ' ; 3 it is 

 the least constant of the divisions : the fourth and last cavity, 

 ' abomasus,' 4 has the usual structure of the true digestive stomach, 

 with a vascular and finely tubular gastro-mucous inner coat. 



In a pigmy Musk-Deer (Tragulus Kanchil), the paunch is 

 of a subglobular form, partially divided into three chambers by 

 the folding inwards of the parietes, forming prominent ridges : 

 the inner surface is beset with filamentary villi, covered by dense 

 epithelium. The second cavity, or reticulum, is less distinctly 

 separated from the rumen than usual : the cells are very shallow, 

 and are lined by dense epithelium. The passage leading from 

 the oesophagus to the third cavity is bounded by two low parallel 

 ridges : the longitudinal lamella? which are characteristic of this 

 cavity in other ruminants are wanting, but as it possesses the 

 dense epithelium, it may be regarded as a rudimentary form of 

 1 psalterium : ' it is partially separated from the fourth cavity by 

 a semilunar fold. This cavity has a smooth gastro-mucous mem- 

 brane : the muscular tunic is thickest at the pyloric end, where 

 a small valvular protuberance projects above the orifice leading 

 to the intestine. This least complex condition of the true rumi- 

 nant stomach represents a stage in its development in the larger 

 species. 



The next modification is more simple than the true ruminant 

 stomach in some essential characters, but more complex in acces- 



1 Syn. ' penula,' ' l'herbier,' ' la double,' (fig. 362, b.) 



2 Syn. ' bonnet,' ' reseau,' ' honey-comb-bag,' ' water-bag,' (ib. c.) 



3 Syn. ' centipellis/ ' maniplus,' ' le feuillet,' ' omasus,' (ib. d.) 

 * Syn. ' la caillette,' ' rennet-bag,' (ib. e.) 



H H 2 



