Gatty Marine Laboratory, St. Andrews. 198 
The coelomic space is richly ciliated, and thus the contained 
cells and granules are kept in active motion, a stream of 
them proceeding posteriorly, and, it may be, escaping by a 
rupture of the body-wall. 
The intestinal canal is enlarged immediately behind the 
anterior region, and such may represent the stomach, for a 
gizzard-like portion is marked off by constrictions in front 
of it. It is ciliated from this region to the vent, and elon- 
gated collections of particles are often observed in motion in 
the interior of the gut. 
Two brownish-green granular glands lie obliquely on each 
side of the gizzard-like portion of the alimentary canal. 
The first or collar-bristles differ from those which succeed 
not only in size but in direction and structure. Each con- 
sists of a long straight shaft, slightly dilated and flattened 
as it approaches the tip which is curved backward, and with 
fine serrations at its rounded base, their size, however, in- 
creasing as the gap is approached, three or four being 
especially prominent next the notch, then the blade has a 
smooth portion, after which the edge is finely serrated to the 
delicately tapered extremity. Amongst these are a shorter 
series of more slender bristles with simple tapering tips. This 
bristle-tult 1s directed forward nearly in a line with the long 
axis of the body, and the bristles are larger and longer than 
those which follow. ‘The three sets of paired bristles which 
succeed are simple and spear-shaped, with slightly curved 
tips, the third or last pair having the tips of the bristles 
somewhat broader. 
The posterior bristles are placed in pairs on each edge of 
the segments of the region, and in outline they somewhat 
resemble an ancient long-toed boot with the sole (edge) 
serrated. ‘They diminish in size from before backward. 
The greenish circulatory fluid is carried forward by a 
dorsal vessel, which is often curved in each segment over 
the alimentary canal, and backward by a ventral trunk. 
In an example from St. Andrews, in which the collar- 
bristles had apparently been broken, the terminal blade was 
finely tapered and translucent without evident trace of 
serrations, whilst the basal web was coarsely spinose. 
The anterior hooks have a long and minutely serrate 
anterior edge, but the main fang inferiorly is short in lateral 
view, and when looked at on end is flattened and bifid. 
‘Lhe posterior hooks do not differ in structure, but are 
smaller. 
Very abundant likewise in British waters is Spirurbis 
