15G 



KUJIISANTIA.- 



-MAMMALIA.- 



-EuMLNANTH. 



Ibese cells are limited by very narrow walls of separa- 

 tion, scarcely elevated above the level of the general 

 surface ; and in the homed ruminants the mucous 

 sm-face is further characterized by a great number of 

 imnute and sharply-pointed conical papillfe, occupjdng 

 every part of the cavity ; being most prominently 

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

 to these sUgbtly-elevated folds of separation a toothed 

 margin. In the camels and llamas the honey-comb 

 cells acquhe 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. 



tlic more temporary or immediate pm-poses which they 

 subserve. The apertures of the cells of tlie paunch, 

 wliich have been designed to retain water for a leng- 

 thened period, are narrow and guarded by productions 

 of the linuig membrane, whilst those of tlie second 

 stomach — destined to be continually parting wilh 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 pamich is marked 

 by a corresponding niunber of vesicvdar bulgings, 

 wliercas, in tJie reticulum, the walls remain imiformly 

 smooth, and do not exhibit on the outside any marked 

 traces of the mternal water-cells ; nevertheless the 

 compartinental subdi\isions are more numerous and 

 complicated than those of tlie first stomach. Another 

 distinction between the ordinary homed and the non- 

 tjqjical hornless ruminants, may be seen in the absence 

 of any mternal cutioidar lining membrane in the reti- 

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

 notice the tliird stomachal viscus. Before doing this, 

 however, wo have to remark, that in all niminants 

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



and anterior margin of the reticulum, constituting tlie 

 remains, as it were, of that portion of the guUet 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 mtercommimi- 

 cation between tlie oesophagus and the tliree first 

 digestive cavities, and it is fimiished -wntli an extension 

 of the muscular tmiics of the guUet, so as to fit it for a 

 two-fold office to be presently described. The thiid 

 stomach, or mninjpUes, D (fig. 53), intervenes between tlie 

 reticulum and the fourth or true digestive caWty; com- 

 municating ^vith the former by a minute apertm-e, and 

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

 of the four great stomachal organs ; but the extent ot 

 its absorbing mucous surface bears no relation to its 

 ilimrnished bidlv, seeing that the latter is enormously 

 increased by a remarkable folding of the intemal fining 

 membrane whose duplicatures resemble the leaves ot 

 a book, whence it is sometimes called the jisaltcrium. 

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

 empty condition of the organ are closely applied against 

 each other. In breadth they exhibit proportionate 

 diflerenoes, so that we iind an alternating assemblage 

 of laminae presenting tliree gi-adations of development ; 

 one forming a very narrow fold, another very broad, 

 and a third of mtermediate width, serially mtercalattil 

 between the two. Altogether about forty such septa 

 may be comited in the sheep, and more tlian double 

 that number in the ox. Internally tlie surface is beset 

 tliroughout with small conical eminences, similar in 

 character to the yWi of the reticidum; those occu- 

 pying the free margins of tlie folds being more conspicu- 

 ously developed. The manAiilies is much elongated 

 in the camels, and considerably larger than tlie water- 

 bag of the same aben-ant group. In all ruminants the 

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

 cavity, being fmictionally and morjihologically analogous 

 to the simi)le gastiic organ of the non-ruminating mam- 

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

 Uie pamich, smooth externally, pyramidal in shape, and 

 temiinates by a narrow tubular portion at the inferior 

 or pyloric extremity, at which position the muscular 

 walls acquire increased thickness. Internally the 

 secretmg membrane is marked by irregularly disposed 

 longitudinal folds, slightly elevated above tlie surface, 

 and intercommunicating by smaller foldings of tlie 

 same nature, ha\'ing a more or less oblique direction. 

 The linuig membrane is soft and smooth, and uistead 

 of beuig provided with villous appendages, is furnished 

 with minute follicular openings leading to gastric 

 glands lil<e those of tlie human stomach. At tlio 

 pyloric extremity, in addition to the ordinary nan'ow- 

 ing usually seen at tliis part, tliere exists a special 

 vahiilar process, developed from the mucous mem- 

 brane at the commencement of tlie duodenum — tliis 

 structure being evidently designed to guard more 

 effectually the cnti-ance to tlie intestinal passage. At 

 tills point, therefore, we are naturally led to explain 

 the function of nmiination, which is characterized by 

 the following phenomena as Uiey successively foUov,- 

 each other under ordinary circumstances : — The food, 

 on being received into the mouth, midergoes a very 

 partial mastication, and in tliis crude state is speedily 



