JOURNAL OF THE OOLLEÖE OP SCIENCE, IMPERIAL UNIVERSITY, TOKYO, 

 VOL. XXX., ARTICLE 2. 



The Errantiate Polychseta of Japan. 



By 



Akira Izuka, 



BigaJcusJd, TtlgulaJmkuslii, 



Prof, of Zoology, Imperial Peers' College, ToTcijo. 



With plaies I— XXI V. 



Introduction. 



Up to tlio present our knowledge of Japanese Polycha?ta has 

 been limited to the following four sources : 



1870. E. Grube. Neue Anneliden aus Japan. 



1879. E. V. Marenzeller. Südjapanische Anneliden. 



1885. W. C. McIntosh. Challenger Report. 



1903. J. P. Moore. Polychaeta from Japan, Kamtscliatka 

 and Bering Sea. 



Limiting our attention to the Polychœta Errantia alone, the 

 number of species belonging to that group and made known 

 ])\' the above mentioned autlu^rs from the Japanese waters, 

 aninunts to seventy-foui- in all. Of tliis number, eighteen species 

 are those tliat liave ])een previously hnown from other parts of 

 the world, while tli(> rest (fifty-six) were described as new. From 

 among tlic latter must ])e deducted tlio two, viz., Eunice congcsta 

 Marenz. and Ghjccra declplem Marexz., which in my opinion are 



