On some new Japanese Land Leeches. 



(Oj'o'bclella nov. gen.; 



By 



Asajiro Oka, Ph. D. 



With Plates XXVIII-XXX. 



Whilst examining a small collection of Japanese leeches in the 

 Museum of the Zoological Institute of this University, my attention 

 was attracted by some specimens of land leeches, totally different 

 from Hœmadipsa japonica Whitman, and since all that was known of 

 this interesting group of animals, as it occurs in this country, was 

 confined to the single species just mentioned, I set to work to in- 

 vestigate these new forms thoroughly. 



The collection contained only 17 specimens, but to these I was 

 able to add others from various l(3calities, from time to time, so that 

 now I have in all ol specimens kept in alcoh(^l, and have, besides, cut 

 10 others into sections in order to examine their internal structure. 

 An acc(3unt of their external characters, and a general outline of their 

 internal organisation are presented in this paper. 



They are so much alike in external features, that at 

 first I took them all to belong to one species, and ascribed the 

 slight but a[)parent differences between some of them to a 

 difference of age. A minute study of them, however, convinced 

 me that I had three distinct species before me, and that these were 



