Gatiy Marine Laboratory, St. Andrews. La 
and comparatively thin, and the divisional strie run to the 
centre, cutting off the hypodermic area. Moreover, though 
the surface of the cup appears smooth to the naked eye, it 
presents under the microscope numerous minute chitinoid 
papille, and, if it has been injured, the cicatrix and various 
irregularities of the divisions are apparent. Occasionally 
abnormalities not due to injury are present. 
The body is, in the preparations, broad in front and 
tapered gradually to the tail, which ends in the anus. It 
is flattened both dorsally and ventrally anteriorly, and, 
indeed, more or less so thro ughout, and marked ventrally 
bya median groove which commences behind a triangular 
area in front and extends to the posterior end of the body. 
The anterior region consists of seven bristled segments and 
the fused peristomial segment, and it is proportionally 
shorter than in Hydroides. The alar membrane is broad 
dorsally, the sides touching in front and separating pos- 
teriorly, whilst the ventral lamella is of moderate breadth. 
The first pair of pale golden bristles is even more widely 
separated than in Hydroides, forming prominent setigerous 
processes a little behind the anterior dorsal angle of the 
alar membrane and collar. ‘The distance between these and 
the next tuft is nearly as large as between the second and 
seventh, and the direction is upward and forward. The 
bristles closely correspond in structure with those of 
Hydroides norvegica and their function is probably similar. 
Hach tuft has a series of strong bristles with long, slightly 
curved shafts which expand a little anteriorly at the 
Shoulder, though some also present a slight convexity 
posteriorly in the same region. On the anterior edge of the 
shoulder are two short conical spurs, whilst the posterior 
half is extended into a long,- tapering, serrated process. 
As. indicated by Fauvel, the region below these spurs is 
roughened by numerous spikes in young forms. They 
afterwards completely disappear. Interspersed with these 
are the long, simple, tapering, curved bristles with minutely 
serrated edges, as in Hydroides. The other bristles of the 
region spring from shorter setigerous processes, have nearly 
straight shafts and slightly curved tapering tips with narrow 
serrated rings. 
Bristles are absent from a great part of the posterior 
region, again reappearing in groups toward the tail. They 
are very long, extremely slender bristles, tapering to a hair- 
like point which is finely serrated. They are longest at the 
commencement of the series and diminish posteriorly, and 
are accompanied by short brush-shaped forms, one outline 
Ann. & Mag. N. Hist. Ser. 8. Vol. xviii. 12 
