320 LEISURE-TIME STUDIES. 



a new species, but apparently an entirely different genus of 

 animals. 



The bearings of this case will be more fully noted here- 

 after, but we may, as a last example of the influence of 

 surroundings on animal existence, mention Fraulein von 

 Chauvin's experiments on the black Alpine salamander 

 (Salamandra atra\ a species of land-newt, living on the 

 Alpine range, at heights of about 1000 feet above the sea- 

 level, and in comparatively dry places. As in all other am- 

 phibians, the young possess gills, but the possession of gills 

 by immature creatures in dry and stony places would appear 

 to place the animals at a singular disadvantage. How, then, 

 has Nature surmounted the difficulty, and adapted the young 

 animals to their surroundings ? Simply by causing the 

 young to undergo their metamorphosis within the body of the 

 parent these animals being ovo-viviparous, that is, retaining 

 the eggs within their bodies until the young are hatched. 

 Thus the young of the Alpine salamander pass their " gilled " 

 condition within the parental body, instead of in water, as do 

 the young of our common newts. But it might be asked, did 

 the young of the Alpine salamander at any previous period 

 in the history of the species, ever live in water; in other words, 

 is their present an acquired condition or not ? Fraulein von 

 Chauvin's experiments supply a clear reply to this question. 



Of two young salamanders possessing external gills, which 

 were taken from the body of the parent and which were 

 placed in water, one died ; the survivor casting off its first 

 set of gills four days afterwards, and actually developing a 

 second and larger set of unusual form, but probably resemb- 

 ling those with which these animals in their original water- 

 habitation were provided. A tail fin was also developed, and 

 for fifteen weeks this young salamander, at a time when it 

 should have been living a terrestrial existence, enjoyed its 

 life in water. At the expiry of that period, however, the gills 

 were cast off, and the animal appeared in the likeness of its 

 land-living parent. Succeeding experiments of Fraulein von 

 Chauvin on the development of the Alpine salamander served 



