236 ' ENDEAVOUR " SCIENTIFIC RESULTS. 



The peristomium is slightly longer than the nuchal 

 segment, from which it is separated by a definite furrow 

 dorsally and laterally ; but on the ventral surface the inter- 

 segmental furrow suddenly bends forwards to form the 

 outline of a " processus oralis," so that the median part of 

 the lower lip appears to be formed by the nuchal segment. 



The lower lip is traversed by short longitudinal furrows 

 along its ventral and lateral margins. 



The body is nearly cylindrical (PI. xliii., fig. 106) ; the 

 parapodia are prominent and widely separated ; the posterior 

 lip of the chaetophore is large, foliaceous, and pointed. 



The dorsal cirrus in the earlier feet is small, being little 

 more than a cylindrical papilla, much shorter than the 

 anterior lip of the chaetophore (PI. xliv., fig. 110) ; it is not 

 till about the 20th segment that it attains the length of this 

 lip (PI. xliv., fig. Ill), and by about the 40th it is as long 

 as the posterior lip and even longer. It has now lost its 

 cylindrical form, has become flattened in the antero- 

 posterior direction, and is highly vascular, and projects 

 outwards almost horizontally (PI. xliv., fig. 112). 



A few small chaetae, as usual in the family, enter the base 

 of the dorsal cirrus and are accompanied by a black aciculum. 

 There is no ventral cirrus, unless the rounded side of the 

 body is regarded as such ; it is separated from the ventral 

 region by a definite groove. 



The chaetae, which are brown, are all capilliform (PI. xliii., 

 fig. 108), with a very slight flange, but are of two sizes : those 

 in the supra-acicular bundle are much longer than the sub- 

 acicular ones. There are usually four black acicula in the 

 main part of the foot. 



In the first and second feet I find the following numbers of 

 chaetae : The supra-acicular chaetae are 10, the sub-acicular 

 8-10 ; in the twenty-first 7 and 14 respectively ; in the sixty- 

 sixth foot the numbers are 6 and 8 respectively. 



The jaws are very dark brown in colour ; the " support " 

 is quite short, not as long as the proximal upper jaw- 

 plate ; each half is a right-angled triangle, the vertical 

 side of which is median, the hypothenuse external, and 

 frayed out, as it were, into a number of delicate short threads. 



The right and left jaw plates are symmetrical, five on each 

 side. The proximal plate (I) on both sides is long and 

 narrow, bidentate, or rather has two large claw-like fangs at its 



