Gatty Marine Laboratory, St. Andrews. Ties 
region the dorsum of the body is slightly convex through- 
out, and the ventral surface is but little flattened and marked 
by a median groove, which runs to the tapered tail with the 
bilobed anus at its extremity. There are about seventy 
segments in the posterior region. 
The general colour of the body is reddish orange, the alar 
membrane anteriorly being paler. The lower tier of the 
operculum is pinkish in lateral view. 
The first setigerous process is separated by a considerable 
interval from the second, and is directed upward and 
forward. It has two kinds of pale golden bristles, viz., a 
series with stout, slightly curved shafts which gently dilate 
from the base upward to the shoulder, beneath which, in 
the larger, is a slight convexity posteriorly. The shaft is 
striated and has a central differentiation or axis which trends 
distally to the long tapering process with a finely serrated 
edge. Anteriorly, the shoulder abruptly ends in two short 
spurs with rounded tips. Three of these bristles toward 
the upper edge of the tuft are larger and longer than the 
others and probably have special functions. The second 
kind of bristle is a slender form with simple, tapering, 
minutely serrated tip often slightly curved, and they are 
distributed over the whole breadth of the fascicle, a few 
shorter forms being visible at the lower edge. 
Six pairs of bristle-tufts follow, their direction being 
obliquely upward and backward. These are simple, rather 
strong, slightly curved, and tapering bristles with narrow 
serrated wings, and in ordinary specimens the tips seem 
to have suffered from friction. 
The posterior region of the body has no bristles anteriorly, 
but toward the tail from nine to eleven pairs of long, 
slender, tapering, capillary bristles appear, decreasing in 
length from the first to the last. They are usually in pairs, 
and are nearly straight, only a trace of a curve being 
observable in their slender tips, which appear to be minutely 
serrated. Moreover, at the base of these are four or five 
brush-shaped forms with a cylindrical shaft and funnel- 
shaped tip with short spikes. 
The anterior rows of hooks are long and pass ventrally 
from the bristle-bundles. Each hook is somewhat polygonal 
in outline, the anterior edge having six strong teeth 
(occasionally only five, im which case they are somewhat 
larger) above the main fang, whilst below it a narrow gulf 
and a prominent prow give a character to the hook. ‘The 
posterior outline forms one of the oblique sides of the 
polygon, the inferior outline being nearly straight, and slight 
