HABITS OF THE AXOLOTL. 481 



several adults from the lartfa, and I have been told that sire- 

 dons in the mountains among the miners' camps near Salt 

 Lake City leave the water and transform. It thus appears- 

 that in the elevated plateaus* as well as at the sea-coast, some 

 siredons transform while others do not. Mexican siredona 

 have for a number of years been bred from eggs in the 

 aquaria of Europe, laying eggs the second year. 



The change from the larva to the adult consists, as we have- 

 observed, in the absorption of the gills, which disappear in 

 about four days ; meanwhile the tail-fins begin to be absorbed, 

 the costal grooves become marked, the head grows smaller, 

 the eyes larger, more protuberant, and the third day after 

 the gills begin to be absorbed the creature becomes dark, 

 spotted, and very active and restless, leaving the water. Their 

 metamorphosis may be greatly retarded and possibly wholly 

 checked by keeping them in deep water. The internal 

 changes in the bones of the head and in the teeth are very 

 marked, according to Dumeril. 



Experiments made in Europe show that the legs and tail 

 of the axolotl, as of other larval salamanders, may be repro- 

 duced. We cut off a leg of an axolotl the first of November ; 

 it was fully reproduced, though of smaller size than the 

 others, a month later. The tail, according to Mr. L. A. 

 Lee, if partly removed, will grow out again as perfect as ever, 

 vertebrae and all. 



The Tritons or water-newts, represented by our common, 

 pretty spotted newt, Diemyctylus viridescens Rafinesque, are 

 also known in Europe to become sexually mature in the larval 

 state when the gills are still present, as has been observed by 

 three different naturalists. The female larva of Lissotrifon 

 punctdtns has been known to lay eggs. 



Order 4. Gymnophiona. The blind snake with its several 

 allies is the representative of this small but interesting order. 



* It 1ms been stated by De Saussure, Cope, Marsh, and more recently 

 by Weismann, that the siredon does not chancre in its native elevated 

 home. No naturalist has seen the Mexican siredon transform into an 

 Amblystoma, but as it does so in abundance in Wyoming and Utah, 

 it probably transforms in Mexico. (The adult Mexican form has recent- 

 ly been found, and is at the Smithsonian Institution.) 



