156 



EUMIXANTIA. MAMMALIA. RUMISANTIA. 



these cells are limited by very narrow walls of separa- 

 tion, scarcely elevated above the level of the general 

 surface ; and in the horned ruminants the mucous 

 surface is further characterized by a great number of 

 minute and sharply-pointed conical papillae, occupying 

 every part of the cavity ; being most prominently 

 marked along the ridges of the laminae, so as to give 

 to these slightly-elevated folds of separation a toothed 

 margin. In the camels and llamas the honey-comb 

 cells acquire a form and capacity strictly analogous to 

 the water-cells of the paunch ; but there are some slight 

 structural modifications apparently conformable with 



Fig. 54. 



Water-cells in the paunch of the Camel. 



the more temporary or immediate purposes which they 

 subserve. The apertures of the cells of the paunch, 

 which have been designed to retain water for a leng- 

 thened period, are narrow and guarded by productions 

 of the lining membrane, whilst those of the second 

 stomach destined to be continually parting with their 

 aqueous contents during the ordinary act ot rumina- 

 tion are patent, and not covered" in by special mem- 

 branous folds. Moreover, in the distended state of 

 the cells, the external surface of the paunch is marked 

 by a corresponding number of vesicular bulgings, 

 whereas, in the reticulum, the walls remain uniformly 

 smooth, and do not exhibit on the outside any marked 

 traces of the internal water-cells ; nevertheless the 

 compartmental subdivisions are more numerous and 

 complicated than those of the first stomach. Another 

 distinction between the ordinary horned and the non- 

 typical hornless ruminants, may be seen in the absence 

 of any internal cuticular lining membrane in the reti- 

 culum of the camels. But we must now pass on to 

 notice the third stomachal viscus. Before doing this, 

 however, we have to remark, that in all ruminants 

 there is situated a short trough-like canal at the superior 



and anterior margin of the reticulum, constituting the 

 remains, as it were, of that portion of the gullet which 

 has not, according to the developing theory, become 

 involved in the first and second great gastric dilatations. 

 This grooved channel forms a bond of intercommuni- 

 cation between the oesophagus and the three first 

 digestive cavities, and it is furnished with an extension 

 of the muscular tunics of the gullet, so as to fit it for a 

 two-fold office to be presently described. The third 

 stomach, or maiiyplies, D (fig. 53), intervenes between the 

 reticulum and the fourth or true digestive cavity; com- 

 municating with the former by a minute aperture, and 

 with the latter by a very wide opening. It is the smallest 

 of the four great stomachal organs ; but the extent of 

 its absorbing mucous surface bears no relation to its 

 diminished bulk, seeing that the latter is enormously 

 increased by a remarkable folding of the internal lining 

 membrane whose duplicatures resemble the leaves ot 

 a book, whence it is sometimes called the psalterium. 

 The leaf-like folds are disposed lengthways, and in the 

 empty condition of the organ are closely applied against 

 each other. In breadth they exhibit proportionate 

 differences, so that we find an alternating assemblage 

 of laminae presenting three gradations of development ; 

 one forming a very narrow fold, another very broad, 

 and a third of intermediate width, serially intercalated 

 between the two. Altogether about forty such septa 

 may be counted in the sheep, and more than double 

 that number in the ox. Internally the surface is beset 

 throughout with small conical eminences, similar in 

 character to the villi of the reticulum; those occu- 

 pying the free margins of the folds being more conspicu- 

 ously developed. The manyplies is much elongated 

 in the camels, and considerably larger than the water- 

 bag of the same aberrant group. In all ruminants the 

 fourth stomach, E (fig. 53), constitutes the true digestive 

 cavity, being functionally and morphologically analogous 

 to the simple gastric organ of the non-ruminating mam- 

 malia. This viscus is about one-third of the size ot 

 the paunch, smooth externally, pyramidal in shape, and 

 terminates by a narrow tubular portion at the inferior 

 or pyloric extremity, at which position the muscular 

 walls acquire increased thickness. Internally the 

 secreting membrane is marked by irregularly disposed 

 longitudinal folds, slightly elevated above the surface, 

 and intercommunicating by smaller foldings of the 

 same nature, having a more or less oblique direction. 

 The lining membrane is soft and smooth, and instead 

 of being provided with villous appendages, is furnished 

 with minute follicular openings leading to gastric 

 glands like those of the human stomach. At the 

 pyloric extremity, in addition to the ordinary narrow- 

 ing usually seen at this part, there exists a special 

 valvular process, developed from the mucous mem- 

 brane at the commencement of the duodenum this 

 structure being evidently designed to guard more 

 effectually the entrance to the intestinal passage. At 

 this point, therefore, we are naturally led to explain 

 the function of rumination, which is characterized by 

 the following phenomena as they successively follow 

 each other under ordinary circumstances : The food, 

 on being received into the mouth, undergoes a very 

 partial mastication, and in this crude state is speedily 



