60 AKT. II. — A. IZUKA : 



posteriorly and changes into a pale white in about the 20th seg- 

 ment. Ventral surface pale white, smooth ; nephridial papillae 

 small, present from the 9th segment posteriorly. 



Prostomium (PI. VII, fig. 1) broader than long; anterior peaks 

 distinct, diverging antero-laterally ; the dorsal groove narrows 

 posteriorly and can be traced to about the middle of prostomium. 

 Ceratophore of median tentacle short and broad, the style 

 being detached. C'eratophores of paired tentacles arise from below 

 that of the median ; slender, distally tapering ; the styles also 

 slender, about IJ times as broad as prostomium. Subtentacles 

 stout, long, distally gradually tapering, about 2|- times as broad 

 as prostomium. All these organs are smooth. Eyes in 2 pairs, 

 brownish yellow in colour ; those of anterior pair slightly larger 

 than those of the posterior. The eyes are not observable in dorsal 

 aspect ; their positions are shown in PI. VII, fig. 2. 



Tentacular cirri slender ; dorsal style a little longer, but 

 ventral style shorter than paired tentacular styles. 



Parapodium (fi.g. 3) large ; bristles long and transparent. 

 Ventral ramus broadly conical, much larger than dorsal ramus ; 

 its tip vertically divided into two plates, a narrower and longer 

 anterior and a broader and shorter posterior. Ventral cirrus 

 slender, gradually tapering toward tip, which extends slightly 

 beyond distal end of ventralmost bristles. Dorsal cirrus as 

 well as its cirriphore large, the latter occupying about ^ the 

 height of parapodium ; style about 4J times the length of ventral 

 cirrus. Acicula straight, one in each parapodial ramus. 



Ventral bristles arranged in a vertical series which spreads 

 out laterally in a fan- like manner, indistinctly separated into a 

 superior and an inferior group. Bristles of the superior group 

 slender, very long, slightly enlarged below the slender, tapering, 



