14 Prof. M'lutosh's Notes from the 



The brancliise are three in number on each side, and have 

 a dull red colour spotted with white. The first pair are 

 about 1 in. long in large specimens, and arise from the 

 second body-segment, which has a spout-like fold at each 

 side. Tiie main stem is often unbranched for some distance, 

 whilst iu others (large) a small branch or two occur close to 

 the base. The whole organ is sub-dichotomously divided, 

 the short terminal divisions giving a character to the mass, 

 which appears to form a dense arbuscle. In many of the 

 divisions the branches spring from one side only, but this 

 does not appear to hold in the distal divisions. The ring at 

 the base of the first bianchia trends evenly away from it to the 

 frill near the external margin of the mouth. A small papilla 

 sometimes occurs close to the base of the second branchia, 

 it may be only on one side ; whilst ventralward the anterior 

 fillet of the segment has a free process like a flat papilla. 

 Close to the outer base of tlie third branchia is the first 

 setigerous papilla, and a short distance ventralward is a 

 similar free flattened process to that described on the 

 previous segment. 



In young examples the branchise are comparatively simple, 

 though the terminal divisions correspond in general struc- 

 ture with that of the adult, and in a small littoral variety 

 from St. Peter Port, Guernsey, the branchise are likewise less 

 bushy, though the terminal branches are typical. 



The setigerous processes are seventeen in number, com- 

 mencing, as indicated, at the third branchia and continuing 

 for sixteen segments thereafter. Each is a somewhat 

 flattened papilla with the bristles arranged in a vertical row 

 in the centre. The first tufts of l)ristles are smaller, the 

 bristles themselves shorter, but they show two groups, as iu 

 the posterior, viz., a shorter series without evident wings, 

 and a longer series also without evident wings, and with 

 slightly curved and tapered tips. In the middle of the 

 bristled region the longer pale golden bristles have st(.ut 

 striated slialts of nearly equal diameter, and tapering tips 

 with wings. Many of these seem to have been broken m 

 life, and show regenerated (?) tips. The striae at the com- 

 mencement of the wings are oblique. The shorter bristles 

 are more translucent, and have either no wings on the free 

 portion or very narrow ones. 



The hooks commence on the segment behind that de- 

 scribed as having the triangular fold in a line with the last 

 branchia — that is, they occur in the segment behind the 

 branchise. At first they are in a single row, but posteriorly 

 in this region they form an alternate double row along the 



