EFFECTS OF CHANGED ENVIRONMENT 213 



directly on the eggs. This seems the more likely since the differ- 

 ences between the two types (in shape of tail, details of bristles, 

 etc.) are not such as we can interpret as the natural direct results 

 of altered salinity. It is well known that slight alterations in the 

 physico-chemical composition of the water have sometimes a 

 great and mysterious influence on eggs and developing embryos. 



FIG. 27. Side view of male Artemia salina (enlarged). (From Chambers's 

 Encyclopedia.) 



Bateson and others have shown that there is great variability in 

 the character of the tail and bristles of Artemia salina, of which A. 

 milhausenii seems to be only an extreme form without tail-lobes. 



FIG. zja. 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 Encyclopedia ; 

 after Schmankewitsch.) 



But if the changes were somatic modifications, it is still open 

 to the critic to point out that Schmankewitsch experimented 

 with a progressively changing environment on a series of genera- 

 tions, and that the results were due to modifications hammered 

 afresh on each successive generation, without there being any 

 inheritance of these modifications. 



A Typical Case. An often-quoted and typical instance was 

 communicated to Darwin by Moritz Wagner. Some pupae of 



