32 THE INFLUENCE OF ENVIRONMENT ON 



hood of the Black Sea were separated from one 

 another by a dam ; of these the upper and larger 

 lake contained water with about 4 per cent, of salt 

 in which Artemia salina occurred in great numbers. 

 The water of the lower lake contained about 25 

 per cent, of salt and had no Artemia living in it at 

 all. From some cause or other the dam burst, and 

 the water from the upper lake rushed down into 

 the lower and smaller one, large numbers of Artemia 

 salina being carried down by the flood. The dam 

 was repaired, and the water of the lower lake, the 

 strength of which had been reduced by the flood 

 to about 8 per cent, of salt, began slowly and 

 gradually to regain its former strength. Specimens 

 of the Artemia were taken out and examined from 

 time to time, and it was found that as the per- 

 centage of salt rose the tail-lobes of the Artemia 

 gradually got shorter and blunter, the hairs got 

 smaller and fewer, and the whole animal gradually 

 became transformed from Artemia salina to Artemia 

 Milhausenii. In about three years' time the water 

 had regained its former strength of 25 per cent., 

 and the Artemice had become completely trans- 

 formed into Artemia Milhausenii. 



Not satisfied with this, Schmankewitsch next 

 tried the reverse experiment. Starting with 

 Artemia Milhausenii he gradually decreased the 

 strength of the water in which they lived by adding 

 fresh water, and had the satisfaction of finding that 

 as the percentage of salt diminished so the tail- 

 lobes of his Artemice became longer and their 

 hairs more abundant, and when the strength of 



