JoHS. Schmidt 185 



These figures have to be compared with the figures of Table III for 

 non-transplanted samples. Such a comparison does not leave any doubt 

 that the number of vertebrae has really been raised by the transplanta- 

 tion: out of the 12 values above 11 are greater than 114, while of the 

 87 values in Table III only 5 are greater than 114. 



It is further shown in Table VI (p. 190) that the average number of 

 vertebrae in offspring of mothers with a given number of vertebrae, 

 e.g. 116, is greater for transplanted than for non- transplanted specimens. 



It is therefore proved to a certainty that the transplantation from 

 the natural conditions at Station 31 to the embanked area raises the 

 average number of vertebrae in the population. It is not possible to 

 decide for certain what factor or factors contribute to that effect. But 

 it is a fact that the temperature in the boxes, placed in quite shallow 

 water, about 2^ meters deep, was higher than at Station 31 and on the 

 whole probably higher than for any natural population of Zoarces in 

 Danish waters. On the other hand the salinity was lower in the boxes 

 than at Station 31, viz. about 12 °/^^ against about 21 "/^^ at Station 31. 

 In the embanked area, where the boxes were placed, and which is used 

 as an eel-farm, Zoarces is only found occasionally and in extremely small 

 numbers, whereas it abounds outside the dam, at Station 31. 



VI. The Zoarces Populations of the Ise Fjord — Roskilde 



Fjord Area. 



Beside the yearly analyses of the populations from Stations 31 and 

 34 we in 1919 carried out analyses of a greater number of populations 

 from the same fjord area. As will be seen from Fig. 1 the Ise Fjord 

 opens into the Kattegat (at the north coast of the isle of Sealand), and 

 Roskilde Fjord is a branch of Ise Fjord. In both ^ords Zoarces occurs 

 in abundance right from the mouth to the base. 



Table VII (p. 191) shows the result of our population-analyses which 

 are also represented in Fig. 1, p. 186. It will be seen that the populations 

 living outside the two fjords, in the Kattegat, have the average number 

 of vertebrae which is characteristic of the populations of the open sea in 

 the Baltic area, viz. 117-118. In the mouth of the Qord the number is 

 114-115. From this the value falls quite evenly in the Ise Fjord to 

 112'2, which is the lowest value for that fjord. In the Roskilde Fjord it 

 falls suddenly to 111*2 (Station 71) and 110'9 (Station 72), reaching near 

 the base of this fjord, at Station 34, the lowest average value hitherto 

 known for any Zoarces population, viz. about 1080. 



