31 



crest of the back and tail had disappeared, and the shape of 

 the head had changed. Irregular spots of a pale yellow 

 colour had also made their appearance on the limbs and 

 body. From a second instance, it appeared that the trans- 

 formation took sixteen days to accomplish, i.e., for the larval 

 to become a perfect form, and that during this time no food 

 was taken. In the course of two years, sixteen of this 

 brood had been thus converted into the Salamandrine form, 

 all the rest remaining larvae still, as was the case with the 

 parent Axolotls, which, with their two male companions, 

 showed no advance whatever upon the tadpole form. Care- 

 ful observation of my own home-bred specimens shows no 

 important change in this direction, although the branchiae 

 have certainly diminished in size, while the animals 

 breathe atmospheric air from the surface as frequently 

 as the fully developed Triton, which has no branchise at 

 all : probably dissection would show considerable develop- 

 ment of the lungs. In one instance only have spots 

 appeared on the sides, and the feet have become partially 

 webbed. 



Even now, Cuvier's surmise that Siredon must be 

 expunged from the list of the perennibranchiates is not 

 established, for the Axolotl, of which we have been treating, 

 turns out not to be Siredon at all, but the larval form of a 

 well-known species of Amblystoma, viz., A. Mavortium ; 

 while the closest search in its native haunts has failed to 

 find any Amblystoma to which the Siredon Mexicanum of 

 Cuvier can be referred as tadpole. 



We have seen that so-called Axolotls may change into 

 Amblystoms or perfect forms, or they may remain inde- 

 finitely in the larval state, and so reproduce themselves. 

 We learn further that : " The eggs laid by Axolotls have 

 been placed both on dry ground and in water, out of which 

 the young could readily emerge. Under the first condition 

 four turned as usual to gilled Axolotls, and two were hatched 

 as perfect gill-less Amblystoms; under the second, four 



