223 THE AMERICAN MONTHLY [Nov 



other experiments^, that the parts of the body of the nor- 

 mal worm from which the segments are taken determines 

 what will be regenerated, rather than the directions in 

 which regeneration takes place. 



vStory of Artemia Re-told. — In 1875 W. Schmanke- 

 witsch published in the "Zeitschrift fur wissenschaf tliche 

 Zoologie" a famous paper giving an account of his obser- 

 vations on the brine shrimp, Artemia salina, from the Bay 

 of Odessa. He stated that by altering the water he could 

 transform A. salina into another species, A. muhlhausenii; 

 and, more than this, that by the addition of fresh water 

 to the habitat in which A. salina lived he could induce a 

 resemblance to the genus Branchipus almost amounting 

 to identity. Both results have been repeatedly criticised; 

 the second has been proved inaccurate, and much doubt 

 has arisen in regard to the first. The most thorough-go- 

 ing criticism, however, has been that of W. P. Ainkin, 

 published in Russian in 1898, but now made available to 

 the unlearned in that language by a summary by N. von 

 Adelung in German. Ainkin points out that the various 

 species of Artemia which have been described do not rest 

 on a satisfactory basis — not that they are alone in that — 

 and that some of them are merely cripple-modifications 

 of A. salina, induced by sudden alterations in the salini- 

 ty of the water. His experiments showed that if the de- 

 gree of concentration was slowly and gradually increased, 

 no structural changes of moment ensued. Some light 

 changes were, indeed, observed, but they were only "mod- 

 ifications," not transmissible to the progeny, and disap- 

 pearing when noi'mal conditions were restored. Moreover, 

 these slightly difi'erent individuals were sometimes found 

 too-ether in the same water. It is to be hoped that no one 

 will imagine that the question is closed, but that we shall 

 have more experiments on Artemia ; in the meantime, 

 however, Ainkin's four general conclusions will be read 

 with interest. The representatives of the genus Artemia 



