120 ToKio Kabukaki 



affinities. Strange to say, the amount of tlie latter element is a great 

 deal larger than that expected. It is an interesting fact that the 

 Oriental elements increase in number, as we proceed towards the south- 

 ern district. So far as we can learn, the species which are not found 

 elsewhei'e amount to about 32, there being included the following forms : 

 Salino formosanus, Aoria hrevianalis, A. taiwanensis, Formosania 

 gilberti, He^nimyzon formoscmwn, Scaplihesthes tamsuiensis, Barhodes 

 paradoxus, Spiniharhns JioIIandi, Leuciscus acliisturus, Zacco ixi.chy- 

 ceplialus, Leuciscidus fitscuSj etc. Some interest attaches to the occur- 

 rence of Opliicephalus maculatus which flourishes in the Philippines 

 and China. There is, however, no room for doubt that it has been 

 introduced by human agency. 



The insect fauna is exceedingly rich and varied, there having 

 been recorded enormous numbers of species and varieties. Up to the 

 present, we are acquainted with about 280 forms of butterflies, most 

 of which are forms known to occur in tropical countries. 



Glancing at the vertical distribution of butterflies, we can distin- 

 guish four zones, viz. the tropical, the subtropical, the temperate, 

 and the subarctic or arctic. Some of the species are, of course, com- 

 mon to two adjacent zones. The tropical forms occur in the plains 

 up to an elevation of about 1,524 m. and are represented by Fopilio 

 aeacus, Pap. aristolochiae, Pap. eriihonius, Hestia leiiconot, KoUima 

 inacliis, Danais tytiay Stichophthalma liowgua, Junonia asferie, etc. 

 Eanging from 1,524 m. to 2,134 m. are such subtropical forms as 

 Pap. liorishanus, Pap. eurons, Lethe insana, L. geviina, Neope ptulalia, 

 etc. The temperate forms occur at a greater elevation, approximately 

 up to 3,048 m. and include such characteristic species as Argynnis 

 papliia, Vanessa xantJiomelas, Ahisara hurni, etc. Extending from 

 the upper limit of the preceding zone to an elevation of 3,658 m. are 

 found such arctic or subarctic butterflies as Colias Kyade, Lethe nii- 

 taJcana, and Oenis sj). 



Of freshwater bivalve shells we find such species as Corbicula 

 producta, C. orierdaUs, Anodonta sioinhoei, TJnio sioinhoei, Nodidaria 

 douglausiae tahvanica, etc. Of those the first is also found in Korea. 



The Loochoo Group. — Composed of some clumps of islands, such as 

 the Sakishima, the Okinawa and the Amami-Oshima, is the Loochoo 

 group, which presents us with animal forms of two different characters, 

 Oriental and Palaearctic, the former types considerably exceeding the 

 latter in numl)er. In reviewino; the faunas of the above-named sub- 



