The sacculated stomach of the Kangaroo, which offers the extreme modification of this organ in the Marsupial order, resembles the human colon both in its longitudinal extent, structure, and disposition in the abdomen. The natural relative position of this singular viscus is, however, very different from that described by Sir Everard Home,* who evi dently has taken his account from the drawing by Mr. Chill, from which ourfg.124 is taken : the object of this drawing, however, being to pourtray the modifications of the inner surface of the Kangaroo's stomach, it is artificially dis posed accordingly. In a full-grown female Kangaroo (Macropus major), I found the abdominal (esophagus four inches long, and terminating at six inches distance from the left extremity of the stomach : this extremity was folded forwards and to the right in front of the (esophagus ; from the basis of the left cul-de sac the stomach continued to expand, and descended into the left lumbar and iliac regions, whence it stretched upwards and to the right side obliquely across the abdomen, to the right bypochondrium, where it became contracted and finally bent downwards and backwards to terminate in the duodenum. The whole length of the stomach, following its curvatures, was three feet six inches, equalling that of the ani mal itself from the muzzle to the vent.
internal surface of the left cul-de-sac was quite smooth and vinous (?), while the right half of the stomach was entirely covered internally with rugw, running chiefly in a longitudinal direc tion, and particularly numerous towards the pylorus." The stomach in the Wombat and Koala does not materially differ in external figure from that of the above-cited Marsupials ; the (esophagus terminates nearly midway between the right and left extremities, but further from the pylorus in the Wombat than in the Koala. The conglomerate gastric gland is of a flattened ovate form, rela tively larger in the Wombat than in the Koala, situated to the left of the cardiac orifice, at the lesser curvature of the stomach (fig. 123). The gastric gland has a similar position in the The stomach of the Kangaroo may be re garded as consisting of a left, a middle, and a right or pyloric division. The left extremity of the stomach is bifid, and terminates in two round cul-de-sacs. The sacculi of the stomach are produced, like those of the colon, by three narrow longitudinal bands of muscular fibres, which gradually disappear, together with the sacculi at the pyloric division. One of the longitudinal bands runs along the greater cur vature, at the line of attachment of the gastro colic omentum ; the others commence at the base of the left terminal pouches, and run, one along the anterior, the other along the posterior side of the stomach : the interspace, between these bands, forming the lesser curvature of the stomach, is not sacculated. The largest of the two terminal sacculi (d, fig.124) is lined with an insulated patch of vascular mucous membrane, which is continued for the extent of five inches into the cardiac cavity ; the epi thelium is continued from the oesophagus in one direction into the nearest and smallest sac culus, and extends in a sharp-pointed form for a considerable distance in the opposite direction into a series of sacculi in the middle compart ment of the stomach (c): this epithelium is quite smooth. The vascular mucous surface recom
mences by a point at the great curvature, near the beginning of the middle compartment, and gradually expands until it forms the lining of the whole inner surface of the right half of the stomach. Three rows of clusters of mucous fol licles (g,g) are developed in the mucous mem brane of the pyloric half of the middle com partment; they are placed parallel with the lon gitudinal muscular bands: about fifteen patches are situated along the greater curvature, and there are nine in each of the anterior and posterior rows. These glandular patches disappear alto gether in the pyloric compartment of thestomach, where the lining membrane is thickened, and finely corrugated; but immediately beyond the pylorus there is a circular mucous gland three fourths of an inch broad : the non-sacculated pyloric division of the stomach was five inches in length.
In the smaller species of Kangaroo the stomach is less complicated than in the Macro pus nurjor ; the number of sacculi is fewer : in Macropus Parryi, Ben. the third longitudinal band at the great curvature of the stomach is almost obsolete : in the Brush-tailed or Rock Kangaroo, ( Macropus penicillatus,) the cardiac extremity terminates in a single sub-clavate cut de-sac. In all the species which I have exa mined the esophagus terminates in the middle division of the stomach, close to the produced crescentic fold which separates it from the cardiac compartment. In the great Kangaroo a second slighter fold is continued from the right side of the cardiac orifice parallel with the preceding, and forming with it a canal, somewhat analogous to that in the true ruminating stomachs, and along which fluids, or solid food not requiring previous preparation in the cardiac cavity, might be conducted into the middle compartment.
I have more than once observed the act of rumination in the Kangaroos kept in the Viva rium of the Zoological Society. It does not take place while they are recumbent, but when the animal is erect upon the tripod of the hind legs and tail. The abdominal muscles are in violent action for a few seconds, the head is then a little depressed, and the cud is masti cated by a rapid rotatory motion of the jaws. This act is by no means repeated in the Kangaroos with the same frequency or regularity as in the true Ruminants. A fact may, however, be noticed as an additional analogy between them ; balls of hair, cemented by mucus, adpressed and arranged in the same direction, are occa sionally formed in the stomach, of which I have met with two, of an oval shape, in the Parryi.