178 Prof. M‘Intosh’s Notes from the — 
of the funnel-shaped tip being longer than the other. The 
posterior bristles have a peculiar fungoid growth which 
forms a blackish coating to the shaft or to the tip. 
The anterior hooks are avicular with four teeth above the 
main fang, which has a well-marked gulf below and a 
preminent prow, which projects about as far as the point 
of the chief fang. The crown is comparatively narrow, and 
the posterior outline is slightly concave, whilst the inferior 
outline of the base is convex with a slight incurvation 
posteriorly. The body of the hook is striated. 
The posterior hooks are smaller, and have, as a rule, five 
teeth above the main fang; the prow is less prominent, the 
inflection of the posterior outline is nearer the base, and 
the basal outline has a more distinct inflection posteriorly. 
Strize likewise pass from the teeth down the body of the 
hcok. The number of hooks in each row is large. Fauvel 
gives a total of six to eight teeth in the posterior hooks. 
Zube either fixed or free, of a rosy or greenish colour, and 
measuring 3 or 4 inches in length, with a smoothly rounded 
and dilated trumpet-like aperture, various lines of growth, 
aud occasionally with a keel more or less rough. Anteriorly 
it is straight or with a wide curve, but posteriorly often 
coiled in a spiral manner. It is attached to shells, masses 
of Cellepora, to rocks, stones, or vases thrown into the sea, 
and is generally solitary, though masses of the tubes 
occasionally occur both in the north and west of Scotland. 
When on the inner surface of the lower (flat) valve of a 
large oyster, the tubes are nearly parallel. In some the 
prolongation of the tube takes place from the narrow (inner) 
edge of the trumpet, and thus four or five prominent rings 
may be formed auteriorly. Fauvel describes seven longi- 
tudinal ridges in the typical form of tube—of which the 
median dorsal is the most conspicuous. 
The dorsal part of the collar in the next species, Poma- 
tocerus triqueter, Li., forms a great free lamella, which, 
probably by accident, is sometimes separated from the 
rest of the collar, and its edges are laciniated, though 
normally it seems to be smooth. The collar continues to 
the ventral surface as a broad membrane usually thrown 
into folds in the preparations. De St. Joseph considers the 
separate parts of the collar dorsally are normal. 
The branchiz are somewhat short, and as usual arranged in 
two lateral fans of thirteen or fourteen (twenty, De St. Joseph) 
filaments, each of which is tapered from base to apex, where 
