22 Pro^. M^Intosli's Notes from the 



The brauchia on eacli side arises by a long trunk in the 

 line of the second larp:e lateral flap (third segment) and 

 quite on the dorsum. The distal region is finely branched, 

 the whole forming a whorled arbuscle so characteristic of 

 the genus. Occasionally a third and smaller stem springs 

 from the segment in front, and its branches have the same 

 arrangement. In an example from Shetland two large 

 branchise of different sizes sprang from the second segment, 

 and two smaller, also of different sizes, arose from the third. 

 In some the whorled condition is conspicuous in tier after 

 tier leading to the somewhat truncate tip. It is noteworthy 

 that the branchiee cling to segments 2 and 3. 



The next segment (fourth) bears a setigerous process and 

 a ridge, but no hooks are present. As indicated, the 

 anterior setigerous processes are dorsal in position, but 

 they soon become lateral. Those in front and rear are less 

 permanent than the median processes. The pale golden 

 longer bristles have nearly cylindrical shafts, the proximal 

 ends being narrowed only for a short distance, and they are 

 finely striated, whilst the distal ends are curved, tapered, 

 and soon end in a fine point, the sides of the tip having 

 well-marked wings. The tip is curved and directed dorsally 

 and posteriorly — that is, the convexity is in front. The 

 shorter bristles have little more than the tips projecting 

 uniformly beyond the surface of the skin, and they show 

 the same form and curvature of the tip. 



The hooks commence opposite the second setigerous pro- 

 cess — that is, the fifth segment — as a single row, and the 

 ridges leave a considerable interval between them and the 

 scutes. The rows remain uniserial till the ninth or tenth, 

 when a biserial arrangement occurs. The hooks have a 

 rather short, stout, main fang, with three or four teeth 

 above it in lateral view, and oblique striae from these to the 

 posterior outline of the neck. Tiie curve below the main 

 fang is slightly angular and wide, whilst the median process 

 on. the anterior outline forms a short cone viith a ])road base, 

 the line then trending at a different angle downward. The 

 posterior outline is nearly straight, very slightly convex, 

 then it bends outward at the point of attachment of the 

 ligament, which passes off above the lower margin of the 

 base, and thus the appearance of the hook is diagnostic. 

 The basal region is comparatively deep, and has a process at 

 its anterior and inferior angle. The long ridges for the 

 hooks cease with the bristles, and thereafter uncinigerous 

 processes project from the posterior border of each segment, 

 the glandular tissue forming a belt between them. Pos- 

 teriorly the processes bear a single row of hooks. 



