the same general direction as the stomach, it next crosses from left to right, twisting slightly; it then enlarges, and reaches the liver, with which it becomes united by a fold of the peritoneum; receiving the contents of the biliary ducts, it bends downwards towards the right side,—is prolonged into the small intestine, which, preforming some convolutions, ends in the large rectal portion almost by intussusception. The rectum is twice as wide as the small intestine, but short and straight, ending in the cloaca, open externally through a longitudinal fissure with swollen lips.[1]
"The intestines are, for the most part, membranous; the first portion of the duodenum has, however, very thick coats, and internally has longitudinal plaiting, which occupies almost all its cavity; in this it repeats the arrangement of the mucous membrane of the œsophagus. This disposition of the fibres leads me to suppose that this part of the intestine has the power of enlarging itself; between these folds there appears a glandulous net-like structure, without doubt of great importance in digestion; this is also observed in the Salamanders.[2]
"In the small intestine, we find a few longitudinal plaits: but these are scarcely visible, and disappear as the intestine approaches the rectum; there is, also, a very minute net-like vascular structure, visible to the microscope. Meckel says, there is some villosity present in the small intestine of Salamanders; but in Axolotl, at least, I could find nothing of the kind. No valve intervenes between the small intestine and rectum,—this latter does not exhibit any longitudinal foldings, unless indeed in its lower extremity, close to the external orifice of the cloaca, where many are seen rising like crests; there are here, besides, four little bodies, like carunculæ. In this cloaca open the urinary and genital organs, and the bladder,[3] not much developed; however, the small intestine, equally with the rectum, is furnished with a fine stratum of longitudinal and transverse fibres, but very delicate and microscopic, and is attached to the vertebral column by a thin band of mesentery.
"Salivary glands are totally wanting; there also seems to be a total absence of pancreas, but this gland is wanting in other Saurobatrachii—in Hypochthon, for example; when existing, it is usually very small, and quite rudimentary. Cuvier does not refer to its existence. The spleen is found; its position I have already alluded to; it is four times as broad as it is thick: it ends in an obtuse point at both extremities. I found it full of rather conspicuous corpuscles, and of black pigment.
"The liver is rectangular, of a yellowish-red colour, with many black spots; its under surface is convex, its upper, concave: the first is connected by the falciform ligament to about the anterior half of the middle line of the lower soft coats of the abdomen, and is divided by it into two unequal portions—these form the two lobes of the liver, the right being the larger. On the under surface, the same division is made, here in a notch extending inwards through about four-fifths of the substance of the liver, enters the umbilical vein, also the biliary ducts and the blood-vessels of the portal system.
"The thin border of the right lobe is notched to receive the small biliary bladder, which, being inflated with air, rises up from the posterior hepatic border, of which it is free. Cuvier says, in the text of his paper, that he was not able to see it; but in the plate accompanying it, it is delineated, though confusedly and incorrectly. It is pyriform, but there is nothing remarkable in its structure; it empties itself, with the bile ducts, united to it, into the duodenum, not far from where the latter is attached to the liver."
- ↑ The external appearance of this fissure differs much in the two sexes—in the male it is, as described by Calori, with swollen and corrugated lips: in the female the orifice is simple, as in many of the Amphibia.
- ↑ We think many portions of the intestinal tract act the part of a kind of secondary stomach. In the Salamanders, as in Triton, we have found, even below the liver portion of the duodenum, widenings of the intestine, to all appearance having the function of second stomachs; perhaps this portion might be regarded as an additional stomach, regarding as duodenum that portion only where it is continuous from it to the liver.
- ↑ In the plate the bladder is represented so as to lead one to suppose it is on the right side; its right position is, as figured by Home, towards the left; its shape varies somewhat in different specimens.
