Fossils from the Upper Musashino of Kazusa and Shiniosa. ]^9 



state of our knowledge of its Molluscan fauna. For the layer to be 

 Pleistocene, there must be some unmistakable evidence, and until 

 that evidence is found, I deem it most expedient to assign to the 

 layer a place in the Upper Pliocene. 



Be the age as it may, there is an important fact which 

 deserves our fullest attention. It is the general character of the 

 fauna in relation to that of the recent as well as of the Lower 

 Musashino from a climatic point of view. If we divide the living 

 species, 232'^ in all, according to their habitat, we get the following 

 result : 



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

 Japan)'^ or in about the same latitudes (Western Japan) 114. 



Percentage of the whole fauna 49. 1 



(2) Species now living in Central or Western Japan as well 

 as north of it (Northern Japan) 45. 



Percentage of the wliole fauna 19.4 



(3) Species now living in Central or Western Japan as well 

 as south of it (Southern Japan) 29. 



Percentage of tlie whole fauna 1 2. 5 



(4) Species now living in whole Japan (Northern- 

 Southern) 16. 



Percentage of the whole fauna 6. 9 



(5) Species now living only in Northern Japan 14. 



Percentage of the wh ole fauna 6. 



(6) Species now living onl3^ outside of Japan 8. 



Percentage of the wh ole fauna 3.5 



(7) Species whose habitat is not accurately known 6. 



Percentage of tlie Avhole fauna ... 3. 6 



1) The species which, thovigh living, have been separated as varieties are not counted 

 in this number. They are Bela tuqulata Ti-, ^ ar, schneideri Harm., PyramideUa virgo Ad. var, 

 btevis Yok„ Macroschisma chinensis Ad. var. laevis Yok., CaUiostoma unicum Dkr, var. shina- 

 gawensü Tok. and Mactfa sachalinensis Sehr, var. imperialis Yok. 



2) Japan, as in my previous paper, has been divided into four parts viz. : Northern, 

 Central, Western, and Southern Japan. Northern Japan is that pnrt of the country lying 

 north of the 38th parallel north latitude, while Central Japan is the part lying south of the 

 same parallel and east of 136° east longitude. Western Japan is the part west of the same 

 longitude, including Chugoku, Shikoku, and Kyushu. Southern Japan is south of Kyushu 

 including the Kyukyu Islands, Formosa and the Ogasawaras or Bonins. 



