136 



AET. II. 



-A. IZUKA 



being of about equal length as the prostominm ; with neither 

 parapodia nor tentacular cirri. 



Parapodium uniramous, with a comparatively large and conical 

 dorsal cirrus, which extends far beyond tip of the bristles. The 

 bristles arranged in a vertical row, grouped into 2 fascicles ; the dorsal 

 fascicle consisting of 5-7 simple bristles (fig. 4) with hooked tip, and 

 the ventral consisting of 8-10 compound bristles (fig. 5). These 

 have the shaft broadened toward the anterior end and terminate 

 with short end-piece, which is hooked at end like the simple bristle. 

 The cfills arise from the dor so -lateral border of seo^ments 

 apart from parapodia. They appear on the ord segment, each 



in the form of a simple 

 filament ; they begin to 

 branch from the 10th or 

 llthsegmont. On 20-25th 

 segments the gills show 

 full development, dividing 

 dichotomously into about 

 10 branches; they remain 

 in nearly the same shape 

 to the end of the anterior 

 ^- of the whole length of the body, after which they gradually 

 decrease in size as well as in number of branches toward the 

 posterior extremity, where a few last segments have no branchial 

 filament. Anal segment with 2 short anal cirri. 



In young specimens the number of filaments to each gill 

 varies according to age ; thus, in the annelid of about 30 mm. 

 length, the gills are all simple ; in that of about 60 mm. they 

 are branched into 2-3 filaments ; and in that of about 75 mm. 

 into 4-5 filaments. 



A segment from the midclle parts of ('oeldbran.clius 

 papillosit.t, showing gills. 8/1. 



