292 Mr. D. Sharp's revision of the 



but when I examined the variations of structure existing 

 in the Batrisi of Europe, North America, and other 

 countries, I found it would not be desirable at present to 

 divide the Japanese forms, most of the genera recently 

 established at the expense of Batrisus being of doubtful 

 validity. The Japanese Batrisi exhibit, however, but 

 little affinity with the European members of the genus, 

 and, if we eliminate them and the members of other 

 widely-distributed genera from the list, we find that the 

 relationship of the Japanese Pselaphidce to those of 

 Europe is limited to the possession of a species of the 

 genus Centrotoma and four of Bythinus, all being, how- 

 ever, distinct species from any found in Europe. On 

 the other hand, the contrasts between the two faunae are 

 very striking. Bythinus forms, in Europe, thirty per 

 cent, of the Pselaphid fauna, whereas in Japan it is 

 reduced to six per cent. One-half of the Japanese 

 genera are not found in Europe, and nearly three- 

 fourths of the European genera have no species in 

 Japan ; while the group Euplectini, forming one- sixth 

 part of the European fauna, has as yet no representative 

 in Japan. The two faunae, then, have only a slight 

 special relationship. Special affinity between the 

 Japanese and North American faunae of Pselaphidce is 

 still less, and is limited to the possession by Japan of 

 three species of the genus Tmesiphorus. Although the 

 Japanese fauna in this department appears thus at 

 present to possess a considerable amount of peculiarity 

 or endemicity (as I have heard it well termed by Mr. 

 Bates), I am far from supposing that this will prove to 

 be really the case, for so little do we know of the 

 Pselaphidce of the Oriental regions of the Eastern hemi- 

 sphere that it is quite probable the whole of the peculiar 

 Japanese genera may be ultimately found in these 

 " terrae adhuc quoad Pselaphidas incognitae," and that a 

 considerable proportion of the actual species may be 

 found in China and the Korea. Our views, too, may 

 still be largely modified by the discovery of fresh forms 

 in Japan itself, for I think it probable that there are at 

 any rate 150 species of the family actually indigenous 

 there, and compared with this number the 67 as yet 

 brought to light appear comparatively unimportant. 



