108 ACQUIRED CHARACTERS sec. 



undoubtedly to be attributed partly to the immediate 

 influence of the external world — for the beginnings of the 

 various organs appeared originally within and without 

 Australia independently, and have evolved themselves into 

 completely analogous structures. 



Besides, we cannot say that other higher forms of life 

 could not have arisen in Australia, for new plants and animals 

 transported thither from other parts of the world get the 

 upper hand of the Australian forms and crowd them out. 



One of my assistants. Dr. Vosseler, has made an observation 

 wliich, if the result is really due to the causes to which he 

 ascribes it, forms a noteworthy contribution to the view advo- 

 cated by me as to the causes of the transformation of forms. 



Dr. Vosseler had at the beginning of the year 1886 (6th Feb., 

 that is now one and a quarter years ago) a number of fully 

 developed young Salamanders (Salamandra maculata) taken 

 from the oviduct of the mother. These he put into a spacious 

 aquarium for subsequent use, where he left some which 

 he completely forgot, and which therefore were not fed. After 

 •the little creatures had remained thus over a year without 

 being properly fed (for the aquarium contained only Algae and 

 a few Infusoria) they were again found. In the whole of this 

 time they had only grown from three centimetres to five centi- 

 metres, and had not undergone any metamorphosis. They had 

 not quitted the water, although it was possible for them to do 

 so, and up till the present day they still remain in the water ; 

 they have retained the large gills, the long tail, and in 

 general all the characters of the larv^, and they lead an active 

 existence as aquatic animals. Investigation showed that 

 these creatures, which usually feed on worms, all kinds of larvae, 

 etc., had nourished themselves with Alcrae tosjether with In- 

 fusoria. They had thus become almost complete vegetarians. 



In other cases, Amphibians, which under natural conditions 

 lose their gills and change into exclusively air-breathing 



