Gatty Marine Laloroiory, St. Andrews. ;»9 



double scries of black clots appears — caused by the ceiitral 

 stalk of" each spatulate bristle. 



Tlic anterior tults of simple bristles (at and after the nintb) 

 arc characteristic wlien contrasted with the northern Chone 

 infmidibiiliforims from Greeulnnd ; for in lateral view the 

 shafts are curved, constricted as they ap})roae]i the wings, situl 

 the tip leaves the shaft at an anjjie, whilst it is finely 

 tempered and bordered with the narrow wings. In antero- 

 posterior view the constriction at the upjjcr end f)f the shsift is 

 distinct, the base of the tip (continuation of the shaft) being 

 eonsiderai)ly broader. On the other hand, the bristles of 

 the Greenlandic species are nineb more slender, the ti])s 

 longer and more attenuate, and the wings just visible. The 

 constriction of tl.c sliaft ])clow and its dilation above the 

 commencement of the tip scarcely attract notice. 



A change occurs at the ninth bristle-bundle, which is now 

 ventral to the row of hooks, for all have tapering tips with 

 the serrate wings, and slant upward and backward. The 

 succeeding tufts are equally powerful, and have the same 

 direction till the posterior liftb is reached, and there the 

 bristles gradually assume an 0|)posite direction — that is, 

 downward and forward. These posfcrior bristles are longer 

 and smoother, presenting no serrations, and the terminal 

 wings narrower, so that the shaft is more conspicuous. The 

 free portion of the bristle increases disproportionately, the 

 shaft being little more than a quarter of the length. Further, 

 whilst the bristles of the anterior region are in front of the 

 median ring of the segment and the hooks behind it, 

 the posterior bristles are more nearly in a line, though still 

 anterior to the row of hooks. Generally speaking, the 

 anterior bristles liave most of their shaft below the skin and 

 a shorter tip, whilst the posterior have a sliort shaft under 

 cover and a long tip — conditions doubtless connected with 

 their functions. 



The rows of books commence on tlie second bristled 

 segment to the ventral side of the bristles, and the first 

 seven — that is, those of the anterior region — are longer and 

 more boldly marked than the succeeding, appearing like 

 minutely dotted dark lines under a lens. The hooks are 

 arranged alternately in a double row, but toward the ends 

 of the row, es})ecially ventrally, appear to form a single 

 series. Each presents a long, curved, striated shaft, deeply 

 inserted into the muscular coats, and taj)ering from the 

 well-marked shoulder to the base. The neck is translucent, 

 linely striated, especially superiorly, narrowed aI;o\e the 

 shoulder, and again slightly dilated as it ap[)roaehis the 



