THE ARCTIC FAUNA. 179 



form with a similar range is the Schizopod crus- 

 tacean Mysis relzcta 1 (Fig. 15), which is clearly a des- 

 cendant of the Arctic marine Mysis oculata> of which 

 it was formerly considered a mere variety. The two 

 Amphipods Gammaracanthus relictus and Pontoporeia 

 ajjinis, and the Copepod Limnocalanus macrurus, are 

 three additional well-known Arctic crustaceans whose 

 range differs but little from those above-mentioned. 2 



FIG. 15. Mysis relicta, a small shrimp-like Crustacean, after Sars 

 (enlarged). 



These facts all go to prove that the sea formerly 

 covered the lowlands of Sweden, Finland, and 

 Northern Russia. The fauna of Scandinavia, as 

 we have seen, indicates that during the greater part 

 of the Glacial period the country was not directly 

 connected with continental Europe as it is now. It 

 seems that the barrier of separation probably con- 



1 The occurrence of this species in Lough Neagh in Ireland, pointing 

 to a connection between the Irish Sea and the Baltic, will be referred to 

 later on; as also that of two allied forms in the Caspian Sea. 



- For additional species with a similar range, vide Nordquist. 



