Gatty Marine Laboratory, St. Andrews. 193 
latus. The shafts are less robust, though straight, and 
they also dilate distally into a flattened process at the com- 
mencement of the tip, but no fine serrations occur on the 
convex edge, the whole being occupied by two to five (Levin- 
sen shows seven) rather coarse serrations, which slightly 
increase in size from below upward in lateral view, the striz 
on the flattened end of the shaft making them conspicuous. 
Then the smooth edge of the “ bite ”’ occurs as it rises to the 
somewhat bellied blade beyond, which, however, soon tapers 
to a delicate extremity, usualiy with a marked curvature. 
The bellied condition of the blade beyond the “bite” is a 
diagnostic feature in comparison with the bristles of Sp. 
granulatus, as also is the comparatively coarse edge, the 
serrations on which point upward and outward, so that a 
certain uniformity prevails. The basal part, moreover, is 
separated only by a slight “‘step” from the distal, and the 
serrations on it sometimes show a slightly different angle. 
Such, however, diverges from the figure of the bristle given 
by De St. Joseph, in which the distal serrations are at right 
angles to the axis of the tip, an error probably due to an 
indifferent microscope. The ‘‘ step” of this bristle shows a 
distinct character when compared with the gap generally 
present in the collar-bristles. The shorter brisstles are 
simple tapering forms. 
The bristles of the second setigerous process are simple 
straight forms, the tapered tips of which are bent backward 
and provided with wings. The four anterior bristles of the 
third series agree with the foregoing in the finely-tapered 
winged tips, but the posterior five have broader sickle-shaped 
tips, with a smooth wing at the base, though the forward 
curve of the sickle-like blade shows long serrations so that 
they are pectinate, the tip being finely attenuate. 
The anterior hooks are in rows of 23-55. Each forms 
an elongate plate, narrower at one end than the other, the 
anterior edge armed with about forty fine teeth. The main 
fang is blunt. ‘The posterior hooks are similar, but smaller, 
and the number in the rows is considerably less (6-18). 
The sinistral tube is shaped like the shell of a Nautilus, 
with a deep umbilicus on the free surface, and its main 
bulk is composed of the last coil, which often hides the 
earlier coils, though, in some, these are distinct in the 
centre. The surface of the last coil is slightly bevelled and 
marked by transverse lines of growth. The aperture is 
circular, though a process of the tube projects beyond it on 
the surface of the sea-weed. The tubes sometimes occur 
in rows and on both surfaces of the Fucus. De St. Joseph 
Ann. & Mag. N. Hist. Ser. 8. Vol. xviii. 13 
