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 he regenerated, rather than the directions in 

 which regeneration takes place. 



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

 witsch published in the "Zeitschrift fnr wissenschaftliche 

 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 normal conditions were restored. Moreover, 

 these slightly different individuals were sometimes found 

 together 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 



