TEANSFOEMATION OF A CliUSTACEAN. 



157 



success, for lie brought Artemia Milhausenii bact to Artemia 

 salina by breeding successive generations in salt water which 

 he made weaker and weaker. Now the differences between the 

 two species are so great that no zoologist had previously cast 

 any doubt on the accuracy of classing them as two species, 



Fig. 42. — Transformation of Artemia saUim to A. Milhausenii. ], tail-lobe of A. salina 

 and its transition through 2, 3, 4, 6, to 6, into that of A. Milliausenii. 7, postabdomea 

 of A. saliTUi; 8, postabdomen of a form bred in slightly salt water; 9, gill of A. 

 Milliausenii ; 10, gill of A. salina. From Schmankewitsch. 



and with all the more reason because each seemed to exclude 

 the other ; Schmankewitsch's experiment has nevertheless 

 proved their relationship, and also explains very simply the fact 

 that they never occur together. It is merely the constancy of 

 the external conditions of life — the greater or less saltness of the 



