1 56 Rumimantia. MAMMALIA. Ruminantia. 
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 papillse, occupying 
every part of the cavity ; being most prominently 
marked along the ridges of the laminse, 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. 51 
Water-cells in the paunch of the Camel. 
the more temporary or immediate purposes u'hich they 
subserve. The apertures of the cells of the paunch, 
udiich have been designed to retahi water for a leng- 
thened period, are narrow and guarded by productions 
of the lining membrane, wdiilst those of the second 
stomach — destined to be continually parting Avith their 
aqueous contents during the ordinary act ot rumina- 
tion — are patent, and not covered in by special mem- 
liranous 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 w^alls remain uniformly 
smooth, and do not exhibit on the outside any marked 
traces of the internal Avater-cclls ; nevertheless the 
compartmental subdivisions are more numerous and 
complicated than those of the first stomach. Another 
distinction betw'een 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, 
Imwever, w'e 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 wdiich 
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 Avith an extension 
of the muscular tunics of the gullet, so as to fit it for a 
tAvo-fold office to be presently described. The third 
stomach, or manyplies, D (fig. 53), intervenes betAveen the 
reticulum and the fourth or true digestive cavity; com- 
municating Avith the former by a minute aperture, and 
Avith the latter by a very Avide 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 AA'hose duplicatures resemble the leaves ot 
a book, Avhence it is sometimes called the psalter ium. 
The leaf-like folds are disposed lengtliAvays, and in the 
empty condition of the organ are closely applied against 
each other. In breadth they exhibit proportionate 
differences, so that Ave find an alternating assemblage 
of laminm presenting three gradations of dcAmlopment ; 
one forming a very narroAV fold, another very broad, 
and a third of intermediate Avidth, seidally intercalated 
betAveen the tAVO. 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 AA'ith small conical eminences, similar in 
character to the villi of the reticidum; those occu- 
pying the free marguis of the folds being more conspicu' 
ously developed. The manyplies is nmch elongated 
in the camels, and considerably larger than the Avatei; 
bag of the same aberrant group. In all ruminants the 
fourth stomach, e (fig. 53), constitutes the true digestive 
cavit}^ 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 oi 
the paunch, smooth externally, pyramidal in shape, and 
terminates by a nariOAV tubidar portion at the inferior 
or pyloric extremity, at Avhich position the muscular 
Avails acquire increased thickness. Internally the 
secreting membrane is marked by irregidarly disposed 
longitudinal folds, sliglitly eleA^ated 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 Avith villous appendages, is furnished 
Avith minute follicular openings leading to gastric 
glands like those of the human stomach. At the 
pyloric extremity, in addition to the ordinary narroAV- 
ing usually seen at this part, there exists a special 
valvular process, developed from the mucous mem- 
brane at the commencement of the duodenum — tl.t 
structure being evidently designed to guard mors 
effectually the entrance to the intestinal passage. At 
this })oint, therefore, avc are naturally led to explain 
the function of rumination, AAdiich is clraracterized by 
the folloAving phenomena as they successively folloAv 
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 
