JOURNAL OF THE COLLEGE OF SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN, 



VOL. XX., ARTICLE 4. 



The Gephyrea of Japan. 



By 

 Iwaji Ikeda, RigahisM. 



With 4 plates 



Only four species of Gephyreans, so far as I am aware, have 

 hitherto been recorded from Japan, viz., Phymosoma japonicum 

 Grube, Dendroséoma blandum Sel. & De Man, Phascolion 

 lucifugax Sel. & De Man and Echiurus unicinctus v. Dräsche. 

 From my studies of the group during several years, 34 more 

 species have become known to me, thus giving in all 38 species 

 to the Gephyrean fauna of Japan as at present known. But of 

 the four previously known species mentioned above, Phascolion 

 lucifugax has, till the present day, remained wholly missing in 

 my collection. 



In this paper I propose to give short descriptions of, and 

 comments upon, all the 37 species directly known to me. 



Of the said 37 species, 26 belong to the Sipunculoids under 

 7 genera and 11 to the Echiuroids under 3 genera. Again, 24 

 species of them seem to be new ; the remaining 13 species I 

 have identified with those which other investigators have described 

 from different parts of the world. It should be mentioned that 



