28 Prof. Mcintosh's Notes from the 



incline to the lateral region, and posteriorly to the ventro- 

 lateral region. The bristles form a vertieal fan in each 

 process — narrow at the base and spreading out distally. 

 Moreover, they are arranged in two alternating series — a 

 longer and a shorter, the tips of the latter only projecting 

 beyond the surface. They are shorter than those of Lanice 

 conchilega and less slender, and the wings are more distinct. 

 Each bristle has a pale base, gently dilates into the widest 

 part of the shaft, then forms a nearly cylindrical and slightly 

 narrower region to the wings, after which it tapers to a 

 slender curved tip. The wings are narrow both anteriorly 

 and posteriorly, where the bristles are shorter. As Grube and 

 Marenzeller point out, the bristles do not, as ]\Ialmgren 

 observes, go to the posterior end, a considerable number of 

 the terminal S3gments being devoid of them. Thus, in an 

 example from Balta about forty of the posterior segments 

 had no bristles. As the tufts of 1)ristles decrease, the un- 

 cinigerous processes become more distinct. In imperfectly 

 preserved specimens the cuticle falls otF and the bristles 

 cling to it by their tips, probably from the enlargement 

 caused by the wings, but the edges of the wings may also be 

 concerned. 



The branchise form two tufts of simple filaments on each 

 side, arising from a transverse ridge in each case on the 

 second and third segments, the anterior ridge being the 

 longer, passing also farther down the side (ventrally) and 

 with more numerous filaments, which are often j)rettily 

 waved in a spiral manner when the animal is at rest. They 

 are of a pale straw or deep orange colour with a red streak 

 in the centre from the blood-vessel «hich is most distinct 

 immediately after a contractile wave of the body drives the 

 fluid forward. As they arise from two segments they can 

 scarcely be called ''one pair," as in the 'Catalogue of the 

 British jNIuseum.' In a young example, half an inch in 

 length, these organs formed two distinct groups on each 

 side, the first containing two or three filaments of different 

 lengths, the posterior only one. They are enveloped in a 

 transparent structureless cuticle, and the bypoderm has finer 

 cells and granules than the tentacles. Longitudinal and 

 circular muscular fibres are also present. The branchiie 

 seem to vary in different races, and some of the largest from 

 the Arctic seas have short thick filaments. 



The bristle-tufts range from thirty to forty-one or even 

 fifty-three {Marenzeller) ^?iU(\. in transverse section the bristles 

 are somewhat ovate, sometimes approaching a short or blunt 

 ellipse. 



