22 Art. 6.— M. Yokoyama: 



latter in Japan, the whole number becomes 13, which is only 

 hj5% of the entire fauna. 



Secondly, what is much more important than the comparison 

 of the Japanese fossil fauna with the foreign is its decidedly more 

 boreal character, when compared with the recent. If we divide 

 the fossil species which are still found living, 148 in all, according 

 to their habitat, the result is as follows: t 



(1) Species now living near the fossil localities (Central 



Japan) or in about the same latitudes (Western 



Japan) 54 



Percen tage of th e whole fauna 36. 5 



(2) Species now living in Central and Western Japan as 



well as north of it (Northern Japan) 34 



Percentage of the whole fauna 23.0 



(3) Species now living in Northern, Central, and Western 



Japan as well as south of it (Southern Japan) ...33 



Percentage of the whole fauna 22. 3 



(4) Species now living only in foreign countries and in 



seas cooler as well as warmer than that of 



Central Japan 5 



Percentage of the whole fauna 3.4 



(">) Species now living only in Northern Japan, or if 

 foreign, in seas cooler than that of Central 



Japan 20 



Percentage of the whole fauna 13.5 



(6) Species uoav known only as deep-sea forms 2 



Percentage of the whole fauna 1.3 



It is noteworthly that, while there are many species which 

 now only live north of the fossil localities, there is not a single one 

 which lives exclusively south of them. These northern or boreal 

 species are the following: 



1) Japan is here divided into four parts, viz : Northern, Central, Western, and Southern 

 Japan. By Northern Japan is meant that part of the country lying north of the 38th parallel. 

 Central Japan is the part situated south of the above parallel and east of the 136th meridian. 

 Western Japan is the part west of the same meridian, including Chugoku, Shikoku and 

 Kyushu, while Southern Japan includes all the islands lying south of Kyushu, that is to say, 

 the Seven Islands, the liyukyus and Formosa. 



