THE AXOLOTL. 375 



the jaws, and two lines of them on the vomer. Cuvier had doiibts about placing the Axolotl 

 amongst the Amphibia with pei-sisteiit branchiae, but he stated that so many witnesses gave evidence 

 in favour of the branchiae not being lost during growth that he was obliged to do so. Time and 

 research have produced a ciirious history about these creatures, and have demonstrated their relation 

 to a perfect and non-branchiate form. 



The Axolotles, furnished witli gills, reproduce by laying eggs, and at first this was considered sufli- 

 cient to determine that they were perfect animals, and that no further growth or change was possible. 

 They were placed by zoologists in a genus of the perennibranchiate Amphibia. But in 1865 M. A. 

 Dumeril saw the Axolotles lose their branchiae, and become altered in shape. They resembled in this 

 the Tritons and Salamanders, or non-branchiate group, and they became Amblystomes, a kind of 

 Amphibian which had been known before. Some Axolotl eggs turned to creatures like the parent, 

 but after a while they lost their gills and became Amblystomes. 



The Axolotles can thus become " by metamorphosis " Amblystomes,* or adult forms. 



Subsequently Axolotles were watched, and the eggs they laid were placed, first, on dry ground, 

 secondly, in water, out of which the young could readily emerge. Out of those under the first condition 

 four turned as usual to Axolotles, and two were born as perfect gill-less Amblystomes ; and under the 

 second four turned to Axolotles and one to an Amblystoma. Then an Amblystoma laid eggs, and 

 they were placed under the circumstances mentioned above, and many more Axolotles wei'e pro- 

 duced than Amblystomes. 



One of the Amblystomes thus obtained laid eggs on a certain 17th of April, and tadpoles were 

 soon produced, and they gi-ew to four inches in length in three months. They presented all the 

 characters of Axolotles, but the colour of the markings of the skin differed. It is evident that the 

 immature Amblystoma (the Axolotl) lays eggs, and that the perfect form (Amblystoma) is not sterile, 

 but can produce eggs, some of which develop into the usual larval or Axolotl forms, and others 

 into Amblystomes, and the surrounding conditions appear to have to do with the direction of this 

 evolution. The Amblystomes are numerous, and have the skin much folded on the body ; the tail is 

 thick and almost cylindrical at the base. They have palatine teeth, forming two transverse rows, 

 which are re-curved, and the tongue is large and fixed inferiorly. 



The Mole Amblystomaf is a little short-tailed dweller in the light soils of the islands on the 

 coast of South Carolina, and its underground retreats can be discovered by the slight upheaval of tho 

 earth which accompanies them. 



The Tailed Amphibia are very sparingly distributed in India, and Dr. Giinther mentions one genus, 

 Cynops, which has species in China and Japan, and another, Plethodon, which is North American, and 

 has one species in Siam. Plethodon persimilis, from Siam, is so similar to Plethodon glutinosus, from 

 North America, that Dr. Gray stated that at a first glance they might be considered to be identical. 



Mr. Wood Mason has noticed a Newt from the Darjeeling Hills, and it is the first from British 

 India. It has horny matter accumulated at the points where the ends of the ribs project against the 

 skin, as in the genus Pleurodeles. 



SUB-ORDER ICHTHYOIDEA. 



These are the lowest, so far as organisation is concerned, amongst the Tailed Amphibia, and 

 present, as it were, the early life of the first sub-order, the Salamandridse. The larval state of 

 these last is persistent in the adult Ichthyoidea, which, more or less fish-like in construction, 

 have in the vertebral column remnants of the notochord, and the vertebral centra are concave in front 

 and behind. Even the teeth on the palate resemble those of fish. In one group of the sub-order 

 the branchiae are persistent, and there are always gill- clefts, and these are called the perenni- 

 branchiata, and in another the external branchiae are not found in adult age, but there are gill-clefts. 

 These are the Derotremata. 



The first group, the PERENXIBRANCHIATA, have long bodies, short limbs, the hinder pair being 

 deficient in some, and the branchiae ai-e persistent in all, and so, of course, are the gill-clefts. 

 Usually, there are no superior maxillary bones, and the palate is armed with rows of teeth. There 

 are three families, and the first is that of the Sirens (Sirenidce), of which the Siren is the type, 

 * Amlliistoma nicxicanus, f Amblystoma talpoidea. 



