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Rh cally refused to believe in the existence of a persistent larval form among the Amphibia. I think, however, it is more than probable that Cuvier's memoir on "Doubtful Reptiles," published in Humboldt's Recueil d'Observations de Zoologie, was seen by Rusconi, or at least heard of by him, as it was read before the French Institute, as early as January, 1807; and this great anatomist insists so strongly on axolotl being a larval condition of some salamander, and saw so many things in its anatomy that he says strengthened him in this opinion, that it is really no wonder the Italian salamander-observer, feeling himself so strongly supported, indulged in a rather contemptuous laugh at our great English anatomist. Cuvier's account of the visceral anatomy is so short, that we venture to subjoin it here; it will be found at page 109 of the work referred to, and is illustrated with several plates. With the greatest deference to the memory of one of the greatest of modern anatomists, and the author of the "Memoirs of the Mollusca," a work which exhibits a wonderful skill in minute dissection, yet I have never met with an anatomical description which seems so decidedly written to prove a foregone conclusion. Cuvier thought axolotl a larval form; through the kindness of Humboldt, he was given specimens, from the anatomy of which much was to be proven; and yet we read such statements as that the "spleen is very small, and in the middle of the mesentery;" that the "oviducts were so very delicate, that one could perceive them with difficulty;" with what justice these facts, tending to prove an immaturity of condition, are stated, will be seen a little further on:—

"In axolotl," writes Cuvier, "the œsophagus is short, plicated longitudinally, and is continuous with the stomach; this latter is large, membranous; the forepart is a little plumpish, but towards the pyloric orifice, it is much contracted. I found it full in the two specimens (examined) of small fresh-water Crustacea, strongly resembling our native ones. The animals had swallowed these without masticating them; and their legs were found undigested down as far as the rectum.

"The intestinal tract is tolerably large; more especially the portion nearest the liver, and tolerably long; it consists of two principal loops, and is furnished neither with a cœcum nor internal valve of any kind.

"The liver is rectangular, and without any deep lobes. I could not detect the presence of a gall-bladder.

"The spleen is very small, and is placed in the middle of the mesentery; this latter is as we find it in the ordinary salamanders. Indeed, all the intestines are just those of a salamander.

"The ovaries are very small, flabby, and contained hardly a trace of ovæ. They occupied the same place, and are furnished with the same greasy appendages that are found in the common salamanders. Again, the oviducts are so delicate (si frêles) that one can scarce perceive them.

"From all these marks of immaturity, and that intimate resemblance which all the viscera bear to those of the salamander and their larva, I conclude that the Mexican axolotl is but the larva of some huge salamander, perhaps the same that is alluded to by Michaux."