232 " ENDEAVOUR " SCIENTIFIC RESULTS. 



The parapodia are prominent ; the dorsal cirri are re- 

 latively large from the first, are vertically extended and 

 flattened antero -posteriorly, leaf-shaped in outline ; con- 

 stricted at the attachment, with rounded apex ; the cirrus 

 increases in size further back, so that by the 29th it is as long 

 as the posterior lip of the chsetophoral sac, and later comes 

 to exceed this in length (PI. xliii., fig. 99). 



Seen under a dissecting lens the dorsal cirrus has the 

 appearance of being folded along its length, as Savigny's 

 drawing suggests ; this appearance is due to the large size 

 of the blood vessel which traverses it, and of the lateral 

 vessels which spring in numbers from it. The internal 

 margin, directed towards the body, rises nearly straight 

 upwards, but the outer margin has a gentle convex curve, 

 which suddenly turns inwards at the base, where it connects 

 with the foot. 



The chsetophore has two fleshy lips, the posterior of which 

 is at least twice as long as the anterior, and much higher ; 

 it is produced outwards as a somewhat conical lobe. There 

 is no ventral cirrus. 



The parapodium is supported by (usually) two yellow 

 acicula ; the chsetse are few. In the anterior feet they are 

 all capilliform, but in the posterior feet two or three golden 

 acicular chsetse replace some of the ventral capilliforms. 



The capilliforms in the upper part of the bundle are longer 

 than those below, decreasing gradually in length from above 

 downwards. Those in the upper part are almost straight 

 or with a gentle curve (which may be artifact), and have only 

 a feebly developed, obliquely striated flange, but in the 

 sub-acicular bundle the capilliforms are bent upwards near 

 their end, and have a wider flange (PL xliii., fig. 100). 



Somewhere about the 50th segment the acicular chsetse 

 appear (most of the chsetse in the lower part of the feet are 

 broken short so that it is difficult to be certain as to the 

 exact segment). These are usually two in number, some- 

 times three, and the two are not alike ; the upper one has the 

 notch separating the two teeth, nearly in line with the axis, 

 that it is almost terminal ; but in the lower chsetse it is 

 more lateral, and the teeth larger (PI. xliii., figs. 101, 102). 



From the 13th foot to the 25th, all the chsetse are capilli- 

 forms, arranged in supra-acicular and sub-acicular bundles ; 

 in the 25th the supra-acicular bundle consists of (a) an upper 

 group of long bristles, 4-5, and (b) a lower of 4 rather shorter 

 ones. The sub-acicular bristles arc still shorter. 



