Volume X OCTOBER, 1920 No. 3 



RACIAL STUDIES IN FISHES. 



IV. EXPERIMENTAL INVESTIGATIONS WITH 

 ZOARCES VIVIPARUS L. 



By JOHS. SCHMIDT, D.Sc. 

 Director of the Garlsberg Physiological Laboratory, Copenhagen, Denmark. 



(With 2 Text-figures.) 



I. Introduction. 



In a previous paper (Journal of Genetics, Vol. vil, 1918) the prin- 

 cipal results of some statistical investigations with Zoarces vivipams 

 were summarized. I there expressed the following view, with regard to 

 the nature of "races" in Zoarces and other fishes as characterised by our 

 population-analyses (I.e. p. 117) : "A fish 'race' is largely a statistical 

 conception. It implies a mixing of different genotypes, and the average 

 values characterising the * race ' are primarily dependent upon the 

 quantitative proportion between these ; only secondarily on the environ- 

 ment." It was further pointed out that we could not expect to arrive 

 at any final decision before the results of those experimental investiga- 

 tions which were carried out along with the statistical investigations 

 with the same species since 1914, were available. This is the case now, 

 at least with regard to some of the experiments which are suflSciently 

 advanced as to be suitable for publication. I propose to give here a 

 summary of some of the most important results. A detailed account 

 will be published later on in the Goniptes rendus des travaux du Labora- 

 toire Garlsberg, Copenhagen. 



Two Zoarces populations are to be dealt with here, both from Danish 

 waters, viz. the Ise Fjord and the Roskilde Fjord, north coast of Sealand, 

 the latter being a branch of the former (see Fig., p. 186). Both popu- 

 lations were mentioned in the paper quoted above and graphs repre- 

 senting the number of vertebrae were given (I.e. p. 110, Fig. 4) from 

 the Ise Fjord (Station 31) and further Fig. 6 (to the right) from the 

 Roskilde Fjord (Station 34). 



Journ. of Gen. x 13 



