E. nomüea: 



Pn 4 *~ 

 ov.s -- 



PD s 



w 



r 



II 



HI 



IV 



VI 



VII 



vi n 



IX 



XI 

 XII 



xni 

 xiv 

 xv 



XVI 



express my best thanks to Prof. Goto 

 for helpful advices and the revision of 

 the manuscript, and to Prof. Izuka 

 for kindly giving me access to his 

 library. 



1. Description 



of Monopylephorus limosns (Hatai 1898) 

 Nomura emend. 



Very sluggish in motion, never 

 executing writhing contractions, but 

 simply retracting like a leech. Colour 

 of the body whitish red, with median 

 longitudinal red blood vessels. Body 

 broadest at the middle and gradually 

 narrowing towards both ends. Prosto- 

 mium conic ally pointed. Brain some- 

 what triangular, emarginate posteriorly. 

 Clitellum imcomplete ventrally, oc- 

 cupies segments XI and XII or some- 

 times segments ^X-JXIII. Set« 



Fig. 1. 



Diagrammatic representation of the principal organs 

 of Monopylephorus llmosus. br — brain, phr — pharynx, 

 g — pharyngeal gland, s c. — gland cells attached to the 

 peritoneum in segments HI — V, œs — œsophagus, chl 

 — ehloragogues, dl i_j — dilated dorsal integumentary 

 vessels, ani_-;— anterior nephridia, as. — anterior sperm- 

 sac, te — testis, spth— spermatheca, ov — ovary, d — 

 dorsal integumentary vessel in segment XI, sp. d — 

 spermiducal chamber, pni... — posterior nephridia. p.s. 

 — posterior sperm-sac, ov.s — ovisac, I — XVI — segment 

 numbers, int — intestine. 



