ANIMALS AND THEIR ENVIRONMENTS. 321 



to reveal other interesting details, supplementing in a remark- 

 able manner that lady's previous observations. Two larvae, 

 the survivors of a set of twenty-three, were placed in water ; 

 one of these young salamanders being somewhat more ad- 

 vanced in development than the other. The younger pos- 

 sessed six red gills of branched form, and of such a size 

 that they appeared to impede its movements in swimming. 

 Soon after being placed in the water, these gills began to 

 shrivel, and were finally rubbed off by the movements of the 

 animal against the sides of the aquarium so that it appeared 

 to be entirely destitute of breathing organs. It lay quiescent 

 in the bottom of the vessel for three days, three new gills of 

 different structure from the first organs being then developed 

 on each side of the head ; whilst the new breathing organs 

 were much shorter than the discarded gills, and did not 

 interfere with its movements in swimming. A new tail fin 

 had also been developed in place of the first with which it 

 was provided, the second appendage being the larger of the 

 two. After fourteen weeks of aquatic life, the gills began to 

 decrease in size, and the tail to become rounded, and in a 

 few days more the young animal cast its skin, quitted the 

 water, and assumed the form, colour, and entire aspect of the 

 adult. The second specimen, which, as already remarked^ 

 was more advanced in development than the first, assumed 

 the likeness of the adult after a much shorter existence in 

 the water. The young appeared to be perfectly at home 

 in the water, and fed greedily when they entered it; this 

 fact being somewhat remarkable in view of the present life 

 and modern development of the species. 



That the present course of development in the Alpine 

 salamander is an acquired condition, and one altered from 

 its original state, there can be no doubt. Its mere relation- 

 ship to its amphibian kith and kin proves this assertion ta 

 be true; whilst the fact that the young will live for an 

 extended period in water, and the mere presence of gills in 

 the young state, place the altered nature of these animals 

 beyond a doubt. The development of useless gills in the 



