A Monograph of the Genris Alarla, 



61 



The absence of Alaria in the Baltic Sea and in the Japan 

 Sea is not to be explained as parallel examples due to similar 

 physical conditions. Within the Kattegat the salinity and tempe- 

 rature lower quickly towards the Baltic Sea. In the Japan Sea, 

 on the contrary, both show higher figures than on the Pacific 

 coast, as can be seen in the following tables. 



I. Mean annual temperatures of sea-w^ater at various 

 parts of Hokkaido. 



II. Mean annual density of sea-^vater at various 

 parts of Hokkaido. 



In the above cited tables the localities are arranged from the 

 eastern end of Hokkaido (Yesso Island) towards the west along 

 the southern coast, then passing the Tsugaru Strait, towards the 



