AXOLO'TL (Gyrinus, Hernandez and Shaw), a genus of .Anaphibia belonging to a group called Perennibranchiate, as they retain their gills throughout life. They are distinguished from other genera of the same family by having four feet furnished with four toes before ' and five behind. This group contains the genera—Axo/otee, Meno bronchus, Proteus, and Sirenus ; and comprises animals which possess at the same time both lungs and gills, and which are consequently organised to live either on land or in water. [Antenatal The Axolotl was the earliest observed of these remarkable animals. At of the Mexican conquest the Spaniards found this animal in great abundance in the lake which surrounded the city of Mexico, to the inhabitants of which capital it then furnished, as it still continues to furnish to their successors, an agreeable and much-esteemed article of food. Hernandez, who seems to be the first writer who actually described the Axolotl, expressly mentions it having been thus used by the ancient Mexicans ; and adds that the flesh was considered as an aphrodisiac, that it was wholesome and agreeable, and tasted not unlike eeL Succeeding authors, without taking the trouble of observing for themselves, were content to copy what Hernandez bad said before ; but distorting his short, description by absurd comments of their own, and adding the figures of far different species, the whole subject became at length involved in such inextricable confusion that finally all memory of the Axolotl was lost, or the animal itself con sidered as a fictitious being. The late Dr. Shaw however, who received a specimen of the animal edirect from Mexico, recognised iu it the Axolotl of Hernandez, as is proved by his having used the generic term Gyrinus in his account of it published in the 'Naturalist's Mis cellany,' which had been originally applied to it by its first describer, though Baron Cuvier seems disposed to deprive the British naturalist of this credit, and to ascribe the sole honour of re-discovering the Axolotl to Baron Humboldt. It is indeed true that Dr. Shaw subse
quently described the same animal in the third volume of his 'General Zoology' under the very different name of Siren pisciformis ; but this only proves that he considered it, as Baron Cuvier was himself afterwards inclined to do, not as a perfect animal, nor in fact as the type of a new genus, but rather as the immature state of some species belonging to a genus already known. To Baron Cuvicr himself however we are indebted for the complete description and elucidation of the form and organic structure of this curious reptile. Two specimens brought by 31. Humboldt from Mexico were submitted to the examination of the French naturalist, whose researches on the subject of their anatomy, compared with that of the kindred genera, are recorded in his 'Recherches sur les Reptiles Douteux,' inserted in the zoological part of Messrs. Humboldt and Boepland's Travels. A detailed examination of all the Batnichiau Reptiles, and more parti cularly a careful investigation into their anatomical structure during the tadpole state, and the gradual change which they undergo in passing from this state to their mature and perfect form, led Baron Cuvier to establish as an unquestionable fact that certain of these animals retain both lungs and gills throughout the entire period of their existence; but whilst he unhesitatingly announced this fact with regard to the Siren and Proteus, ho was disposed to consider the Axolotl as the tadpole of some of the larger species of American salamanders—an error induced as well by the general similarity which these animals bear to one another as by the immature age of the specimens of the Axolotl which were submitted to his observation. Succeeding naturalists adopted 3L Cuvier's views upon this subject; but that great zoologist himself subsequently altered his original opinion, and candidly confesses in the second edition of the Regno Animal' that the concurrent testimony of all original observers over balances the mere deductions of the physiologist, however plausible or apparently well founded.