ON A NEW SPECIES OF DEEP-SEA FOI.YCIEETA. 



27 



rarau?. In fig-. 4 it is concealed by the branchial tubercles, but is 

 visible in fig. 5. This figure represents the 38th segment, seen likewise 

 in posterior view. It is considerably longer than that shown in fig. 4 

 and just described. There exists on the dorsal side a cirrus (fig. 5, dc.) 

 instead of an elytrum. The dorsal cirrus, consisting of a basal and a 

 short distal segment, is not longer than the longest branchial tubercle. 

 The end of the ventral cirrus does not reach the distal end of the 

 parapodium, being only about one-third the length of the latter. 



The branchial tubercles are more numerous, and are distributed 

 over a broader area, than in the parapodium before described. The 

 setae, the acicula, the hairs, &c, are essentially similar to those of the 

 latter, so that they need not be specially described. 



The elytra are borne on the segments 2, 4, 5, 7, 9, 11, &c., which 

 thus alternate regularly, except in the case of segments 4 and 5, with 

 those in which the parapodia are provided with dorsal cirri instead 

 of elytra. 



The elytra of the first pair are large and elliptical in shape ; they 

 meet in the median line, covering over not only anteriormost segments 

 but also the cephalic lobe as well as a part of the ommatophores. The 

 elytra of the second pair are roundish in shape, and smaller than the 

 first, being only about half as large ; the point of insertion of the 

 peduncle to the elytrum is situated nearer to the lateral than to the 

 median border. 



From the third elytra backwards the size gradually increases. On 

 the I Ith segment, the median zone of the dorsal surface left uncovered 

 by its elytra is about twice as wide as the diameter of the elytra them- 

 selves. More posteriorly, as the breadth of the body diminishes, the 

 elytra still continue to enlarge, so that the uncovered zone of the 

 dorsum becomes continually less and less wide. 



The dorsal cirrus in the third segment extends beyond the tip of 

 the parapodium, being about twice as long as the latter. Posteriorly 

 the dorsal cirri become smaller together with the parapodia themselves. 



The ventral cirrus in the second segment (or the first elytra-bearing 



