170 



I. IJIMA AND T. KABURAKI. 



running, ill-defined darker bands. Ventral surface lighter ; the course of 

 longitudinal nerve-cords indicated by two dark lines. 



Eyes small, numerous, 

 found along and close to 

 margins of head, on both 

 sides extending behind to 

 about the second pair of 

 gut branches. They are 

 arranged in a single row 

 in the smaller specimens ; 

 but in the larger ones, 

 they may be increased to 

 such a number that sever- 

 al are found in the width 

 of the occellated zone, 



W especially in the anterior parts of head. A gap in the zone may 

 occur in the middle of frontal margin, separating it into right and 

 left zones. 



Mouth at about the hind end of the middle third of body. Pharynx 

 insertion situated a short distance in front of the middle of body. Anterior 

 gut trunk with 5-7 pairs of branches ; posterior gut trunks each with about 

 15 lateral branches. 



Genital aperture situated nearly midway between mouth and hind end 

 of body, leading into long and canalar atrium. Testes numerous, situated 

 ventrally along both sides ot anterior gut trunk and extending from ovarian 

 region to insertion of pharynx. Vasa deferentia opening separately into 

 moderately wide vesicula seminalis, which passes behind into slender 

 ejaculatory duct. Penis small, its muscular wall not sharply defined from 

 surrounding mesenchyme ; horizontally disposed, the free end but little 

 projecting into the widened anterior end of canalar atrium. Ovaries two, 

 placed ventrally in front of the first pair of gut branches. Course of oviducts 

 could not be distinctly traced in the few mature or nearly mature specimens 



