62 Racial Studies in Fishes 



to particulars of the diallel crossings I refer to a previously published 

 memoir'. 



The experiment her6 described was carried out during the winter 

 1918—1919. On the 10th of December 1918 diallel crossings were 

 performed with 7 specimens of trout, viz. 3 males indicated by x, y and 

 z and 4 females {a, b, c, d). From this arose 12 different offspring- 

 combinations. The larvae hatched out about April 10 and were killed 

 and preserved on May 15, 1919, when the yolk-sac was just resorbed. 

 The experiment was carried out in the south of Jutland at the 

 " Kongeaa " (Kingsriver) by Mr A. Christiansen. The countings were 

 made by Mr Vilh. Ege, M.Sc. 



The character examined was the number of vertebrae, of which the 

 parents exhibited the following : 



<^ a- 59 2/60 z 59, 



^ a 61 6 59 c 57 (^ 58. 



For each offspring-combination 50 specimens were examined, in 

 which the number of vertebrae were counted under the microscope, and 

 after this the average was calculated for the 50 specimens of each 

 combination. 



With notations that indicate an offspring-combination by the 

 symbols of the parents the results were as follows : 



TABLE 1. 



Avej'oge number of Vertebrae in Offspring (50 specimens of 

 each combination). 



In this table the offspring-combinations of a horizontal row have 

 the same father, and those of a vertical row have the same mother. 



1 Jobs. Schmidt : " La valeur de I'individu a titre de generateur, appreciee suivant la 

 m^thode du Croisement diall^le" (Comptes Rendus des Travavx du Laboratoire Carlsberg, 

 Vol. XIV, No. 6, Copenhague, 1919). 



