EFFECTS OF CHANGED ENVIRONMENT 213 



Experiments on Brine-shrimps. — Reference is often made 

 to the observations and experiments of Schmankewitsch (1875) 

 on certain brine-shrimps belonging to the genus Ariemia. By 

 lessening the salinity of the water he was able to transform one 

 type, Artemia salina, in the course of generations into another 

 type, Artemia milhansenii. By increasing the salinity, he was 



Fig. 27. — Side view of male Artemia salina (enlarged). 

 EncyclopcBdia. ) 



(From Chambers's 



able to reverse the process. Although he did not himself make 

 any such claim, his work has often been referred to as an 

 illustration of changing one species into another, and of the 

 inheritance of acquired characters. 



Fig. 27a. — Tail-lobes of Artemia salina (to the left) and of Artemia mil- 

 hausenii (to the right) ; between these four stages in the transforma- 

 tion of the one into the other. (From Chambers's Encyclopaedia ; 

 after Schmankewitsch.) 



It seems very doubtful, however, whether we have here to 

 do with modifications at all. Schmankewitsch did not modify 

 any one Artemia salina into Artemia milhausenii ; with a pro- 

 gressively changing environment and in the course of generations 

 he observed a transition of the population from the one type to 

 the other ; it is probable that the change of salinity operated 



