38 ART. II. A. IZUKA : 



The central region of the dorsum is left uncovered throughout 

 the greater part of its extent. 



In about the 20tli parapodium the dorsal ramus is represent- 

 ed by a conical papilla, containing an acieulum ; dorsal bristles 

 absent. The ventral ramus is pointed superiorly and obliquely 

 slants off inferiorly, containing a large acieulum. Bristles in two 

 dense groups ; the dorsal or smaller group consisting of slender 

 forms with elongated spinous tip, ending in a slightly hoolscd 

 point ; the ventral group consists of bristles, the tip of which shows 

 a short terminal hook with a spur beneath and a series of relatively 

 long spinous rows (Woodcut B.). 



In the 50th parapodium the general structure remains the 

 same ; and between the two groups of bristles in the ventral ramus, 

 there occur two especially strong bristles (Woodcut A), which have 

 shafts 4 or 5 times thicker than an ordinary bristle. 



Habitat : — Off Kobe, Japan, 50 fathoms (" Challenger "). 



JPolj/noë cnrinata Moore. 



1903. Hylosynda carinata, Moore. Proo. Acad. Nat. Sc. Pliilad. Vol. 

 LV, p. 417, pi. xxiii, figs. 16, 17. 



J. P. Mooee's description of this species is based on a frag- 

 mentary specimen consisting of prostomium and 26 anterior seg- 

 ments. Length of the fragment 26 mm. and breadth including the 

 bristles at 10th segment 10.5 mm. The principal characters, as 

 embodied in his description, are as follows : — 



Prostomium very short, twice as wide as long ; anterior margin 

 with a deep median sulcus, on each side of which the broadly 

 rounded prostomial lobes pass directly into base of lateral tentacles ; 

 lateral margin strongly convex ; posterior margin nearly straight. 



