HYDROIDES NORVEGICA. 351 
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 1s 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 
similar to those of Serpula vermicularis (Plate CX XX, fig. 10), 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, and another at the shoulder anteriorly. The shaft is striated 
and has a central differentiation or axis, which trends distally to the long tapering process 
with a finely serrated edge. Superiorly the shoulder abruptly ends in two short spurs (horns 
of some) 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 simple slender form (Plate CX XX, fig. 9) 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 (Plate CX XX, figs. 9 and 9’), 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. More- 
over, at the base of these are four or five brush-shaped forms with a cylindrical shaft and 
funnel-shaped tip with short spikes (Plate CX XX, fig. 9a). 
The anterior rows of hooks are long, and pass ventrally from the bristle-bundles. Hach 
hook (Plate CX XX, fig. 9b) is somewhat polygonal in outline, the anterior edge having six 
strong teeth (occasionally only five. in 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. Slight strie cross the body of the hook obliquely. ‘The number of hooks 
in these long rows is great, and the pigment-line indicating them remains after removal of 
the cuticle and hooks. 
The posterior hooks (Plate CX XX, fig. 9c) have the posterior outline considerably 
lengthened so as to alter the character of the hook, and give it a resemblance to that often 
seen in the Ampharetide and Terebellide. They have four teeth above the chief fang, 
which is proportionally larger than in front, and the basal outline is slightly convex. Oblique 
strie are also present on the body of the hook. The ligament, as in the anterior hooks, is 
attached to the angle between the posterior outline and the base. 
Reproduction—De St. Joseph (1898) describes the egys as reddish, and the sperms as 
minute with a refringent head. Dalyell (1853) figures reddish ova on the plate with the tubes 
and annelids, but no reference is made to them (fig. 7). A young example from Lochmaddy 
was developed on the blade of a tangle. At Naples Lo Bianco (1909) found that two species 
of this genus, viz., Hydroides pectinata, Phil., and H. uncinata, Phil., were mature—the former 
