302 



STOMACH AND INTESTINE. 



will be necessary briefly to state its pecu- 

 liarities in each. 



In the Canrivora the shape of the stomach 

 approaches that of the human organ : it has 

 a cardiac pouch, and a greater and lesser 

 curvature. The intestine is short, its 

 length being to that of the body as* 5 to 

 1 in cats and dogs, and 8 or 9 to 1 in the 

 hyaena and bear, but reaching 15 to 1 in the 

 Phoca vitalina, one of the amphibious seals. 

 The mucous membrane is destitute of folds. 

 The convolutions of the small intestine are 

 few and simple. The caecum is short, and 

 scarcely wider than the rest of the large 

 intestine.f And the latter segment of the 

 canal is short, wide, and cylindrical. 



The Insectivora have a very similar intestinal 

 tube. The simple and elongated stomach is 

 transverse to the axis of the body. In some 

 genera, its spherical cardiac pouch is enlarged, 

 while its lesser curvature becomes shortened. 

 The intestine is short from three to six 

 times the length of the body ; it has no 

 caecum, and a nearly uniform diameter. Its 

 mucous membrane exhibits zig-zag folds, 

 which run longitudinally throughout its whole 

 length. 



In the Cheiroptera three chief varieties of 

 stomach have been distinguished by Cuvier. 

 The first approaches that seen in the preceding 

 order, and belongs to those members of this 

 group which feed upon insects. Here the 

 nearly spherical organ has a cardia and 

 pylorus, which are situated close to each 

 other. The second form is seen in those 

 which subsist by sucking the blood of animals : 

 it differs from the preceding in being longer, 

 and more conical from cardia to pylorus. 

 The third, which obtains in the frugivorous 

 division, is very different from both the pre- 

 ceding. 



Thus, in the Pteropus the stomach is a 

 long tube, placed transversely to the axis of 

 the body. One-third of its length is formed 

 by the cardiac pouch, which lies to the left of 

 the cesophageal aperture, and is divided into 

 two bv a slight constriction, while its terminal 

 or pyloric third is bent back so as to be 

 parallel and near to the middle portion. The 

 mucous membrane of this stomach is folded 

 longitudinally ; the left subdivision of the 

 cardia is smooth, and the lower part of the 

 oesophagus which is somewhat dilated 

 differs from the upper. 



The pylorus is well marked in all the 

 Cheiroptera, and the intestine, which is much 

 narrower than the stomach, and is devoid of 

 caecum, is of nearly uniform diameter. It 

 often presents concentric windings or coils. 

 Its length varies greatly ; thus, in the frugi- 

 vorous Pteropus it is six or seven times, in 

 the insectivorous Bat only twice, the length 

 of the body. 



Edentata. The stomach of this order 

 differs greatly in different genera. Most of 

 them possess a simple organ ; the cardiac 



* We owe these measurements to Meckel. 

 j- In the dog it is convoluted. 



pouch of which is large and globular, while 

 the pyloric extremity is conical, and is some- 

 times almost absorbed into the spherical 

 cavity. A single genus, the Mains, adds a 

 further distinction to these two parts in the 

 shape of an internal fold of mucous mem- 

 brane ; and one of its species exhibits a long 

 blind sac, springing from the right of the 

 pyloric aperture. In the Tardigrade genera 

 the stomach assumes much of the complexity 

 seen in the Ruminantia. For it has two cavities, 

 a cariliac and a pyloric, which, if regarded 

 from the exterior, look like mere exaggera- 

 tions of the distinction mentioned above, 

 but, when examined internally, are seen to be 

 divided by prominent folds, and by differences 

 in the character of their mucous membrane. 

 Thus the cardiac pouch has a dry epidermoid 

 lining, and is subdivided by a fold into two 

 parts, and prolonged into a short blind tube, 

 while the pyloric sac has a soft and delicate mu- 

 cous membrane, and more muscular parietes. 

 And its interior is also subdivided, by a fold 

 of membrane, into a terminal part, which is 

 analogous to the fourth stomach of the Ru- 

 minants, and an intermediate cavity, which 

 resembles the third stomach of the same 

 order in its possessing dentate processes, and 

 a direct communication with the oesophagus. 

 The latter tube also exhibits a cul-de-sac, 

 which is sometimes further divided by folds. 



The form and length of the remainder of 

 the canal is subject to great variety. Its 

 mesentery is very long. In many genera 

 there is no distinction of the intestine into 

 large and small. In some there is no trace 

 of a caecum. In others there are two of these 

 tubes, which occupy the confines of the lanje 

 and small intestines, and open by what are 

 sometimes extremely minute apertures.* 



The Ruminantia are remarkable for the com- 

 plete subdivision of their stomach into four dis- 

 tinct cavities. The first of these, the rumen, or 

 paunch, is generally of very great size. It is 

 situated to the left of the oesophagus, from 

 which it receives the food when first swallowed : 

 it has a villous texture, but its minute conical 

 processes are covered by a dense white pave- 

 ment epithelium. The second cavity, the 

 honeycomb or reticulum, is so called from the 

 appearance of its mucous membrane, which, 

 in all other respects, has the same structure 

 as that of the preceding cavity. The third 

 portion, the maniplics or psalterium, is named 

 from the many longitudinal plies or folds 

 which occupy its interior. In the Camel, the 

 circumference of the cells or excavations 

 of its reticulum and paunch have been long 

 recognized as containing muscular fasciculi, 

 the contraction of which enables these cavi- 

 ties to retain water free from admixture with 

 the general contents of the stomach. And 



* In such a case they can hardly be supposed to 

 receive faecal matter. But in the Dasypus muste- 

 linus, the ileum ends by a slit between the larger 

 apertures of two such tubes ; and hence appears to 

 admit of being closed by the lateral pressure of their 

 contents. (See Prof. Owen's Catalogue of the Hun- 

 teriau Museum, vol. i. p. 219. 729 A.) 



