21 



Table VII. Viviparous blenny {Zoarces viviparus). 



shown, abl. 118 and 109, i. e. Ihey exhibit an average difference of not less than 

 9 vertebrae. 



The difference between the average nnmber of vertebrae in the European and 

 the American eel is abl. 7.5. We find therefore, that samples of Zoarces taken 

 from closelj' adjacent localities in the Danish waters may differ one 

 from another as regards number of vertebrae to a higher degree than 

 does Anguilla vulgaris from A. rostrala in respect of the same character, the best 

 one known for distiguishing between the eels of Europe and those of America. 



Fig. 3 gives a graphical illustration of the number of vertebrae in the two 

 samples of European and American eels previously referred to in the present Report 

 (p. 6). It is interesting to compare this with Fig. 2, which shows the two samples 

 of Zoarces from Bornholm and the North Sea (Esbjerg). It will immediately be 

 seen that the Zoarces from Bornholm stand in very much the same relation to 

 those from the North Sea as the European eels to the American, the difference in 

 number of vertebrae being about the same. 



Similarly, there can, between two samples o{ Zoarces from different localities in 

 the Danish waters, be found as great — or greater — difference in regard to average 

 number of pectoral rays, as between the European and the American eel in this 

 respect. 



A main result of our variational -statistical comparison of the Zoarces samples 

 with those of the eel will thus be the the following: that Zoarces viuiparus in the 

 north of Europe is divided up into numerous distinctly different 

 stocks or populations according to localitj', whereas all the eels of 

 Europe are identical. 



The relation between two samples of Zoarces will thus be comparable, not with 

 that between two samples of European eels, but with that between the European 



