18 THE ZOOLOGIST, 



a more diversified adaptability, than the adults. At the same time 

 the young of forms highly specialized often do not exhibit, to any 

 pronounced degree, the distinguishing features of their parents. 



Clearly, under changing external conditions, some amount of 

 flexibility during growth is as essential to the species as it is to 

 the individual. This flexibility differs both as to degree and 

 direction (quality), and is manifested in what may be called their 

 respective characteristic tendencies. Having attained maturity, 

 the race, like the individual, has become more specialised in its 

 mental and physical constitution. But the acquired comparative 

 rigidity, while affording protection against temporary shocks 

 which might have proved fatal during growth, constitutes in itself 

 the primary cause of incipient decay. 



3. B. variabilis, Pall. — Much remains to be done before the 

 distribution of this species in the Grand Duchy is anything like 

 accurately determined. Judging by the accounts from the 

 countries surrounding Baden, whose Herpetology has been more 

 thoroughly investigated, we should expect it to be pretty uni- 

 versally distributed here, as it occurs, more or less abundantly, 

 in all of them. 



I have been unable to find it in the vicinity of Karlsruhe, and 

 should be careful in crediting statements of its existence not 

 capable of ocular demonstration, as there is much confusion be* 

 tween this and the two foregoing species. It is said to occur as 

 near the capital as Ettlingen (five miles south), and again at 

 Heidelberg ; Leydig cites it from Weinheim in the north. 



In the Palatinate variabilis appears to be very common near, 

 and in, the towns of the Khine Valley. It has been recorded from 

 every part of Germany, though it seems to be absent, or very 

 rare, in certain districts. 



I was surprised to come across this species in the island of 

 Lipari, during a short stay there in the early spring of this year. 

 The tadpoles were abundant in the three rivulets of warm 

 mineral water which run down to the sea on the western part of 

 the island (Prof. Giglioli has kindly written to say that he also 

 found it there in 1878). How it reached this volcanic island, 

 destitute of fresh springs, and has succeeded in establishing itself 

 there, is at present a mystery. 



At the time of my visit all animal life was very poorly repre- 

 sented, owing to the stormy wenther ; still I venture to append 



