132 ART. II. — A. izuka: 



tacles 5, the median longest and reaching to the 2nd parapodiated 

 segment (or twice the length of prostominm) ; inner laterals 

 shorter than the median tentacle ; outer laterals still shorter, being 

 |- the length of the median. A small ill-defined eye-spot can be 

 made out between the bases of lateral tentacles on each side. 

 The two succeeding segments have neither parapodia nor tentacular 

 cirri ; and their segmental junction is only indicated by a transverse 

 groove on the dorsal side. The total length of these two segments 

 equals that of the three next following segments ; thence posteriorly 

 the segments become gradually shorter, and in the 20th the 

 breadth is more than 8 times the length. 



Parapodium as usual with a rather long dorsal, and a short 

 somewhat conical ventral, cirrus. Bristles well developed, and of 

 3 kinds : 1) slender, weakly sigmoid, setose bristle with a narrow 

 wing ; 2) compound bristle, with tip of the shaft greatly enlarged 

 and with long, finely tapering blade ; 3) pectinate bristle, with 

 numerous short spikes guarded by a comparatively large tooth 

 on each side. 



Branchia begins to appear as a simple filament on 30th or 

 36th segment, but soon becomes branched, attaining maximum 

 development with 4 or 5 filaments on about 80th segment ; then 

 it remains in the same condition to about the 200th ; and more 

 posteriorly it is reduced in size as well as in number of filaments ; 

 the posteriormost 15-20 segments without branchiae. Anal 

 segment with 2 long and 2 very short anal cirri. 



Maxillary forceps gently curved (fig. 15) ; great dental plates 

 with 4 teeth on the left, and 5 on the right. An accessory piece 

 on each side of the curved lateral plate. 



Mandibles posteriorly divergent (fig. 16) ; their anterior 

 broader ends with a pair of somewhat rhomboidal dental plates 



