JOURNAL OF THE COLLEGE OP SCIENCE, TOKYO IMPERIAL UNIVERSITY, 

 VOL. XXXV., ART. 9. 



On the Aquatic Oligochsete A^ 



3Ionopylep1iorus limosus (Haï ai). 



By 



Ekitaro Nomura, RigakusM. 



Sanuma Middle School, Sarmma, Miyagi Ken. 



With 30 Text Figures. 



JUN 9 191 

 C'onal Muse> 



Soon after its publication Rhizodrilus Smith (1900) was united 

 with Vermiculus Goodrich (1894) by Michaelsen (' Oligochaeta ' 

 1900) to form the genus Rhizodrilus Smith et Michlsn., and Vermiculus 

 was later identified with Monopylephorus Levinsen (1883) by 

 Ditlevsen (1904). Among my collections of aquatic oligochsetes 

 made in gutters and ditches of Tokyo, I have found a species 

 which shows the main generic characters of Monopylephorus, and 

 which must be identical with Vermiculus limosus Hatai, although 

 there are many important differences between its characters and 

 Hatai' s descriptions, which almost induced me for a time to describe 

 it as a different species. Its identity with Hatai's species may 

 however be regarded as certain, inasmuch as in my fairly extensive 

 search in different localities in Tokyo, no other species at all 

 approaching to that of Hatai could be found. My criticisms on 

 Hatai's descriptions will be found under the respective headings. 



Before entering into the subject of this paper I beg to 



