Gatty Marine Laboratory, St. Andrews. 177 
elevations ventrally. Eleven papille occur along its free 
edge in extrusion, and besides a pair at each lateral angle. 
The upper teeth bite to the left of the lower. The first pair 
of scales are rounded, the rest more or less reniform, the ante- 
rior four being more or less rounded (PI. III. fig. 6). Their 
surface is smooth and they are thin. Along their external 
margin are ten or twelve long slightly tapered cilia, the shorter 
forms being anterior. In the posterior scales the cilia diminish 
to two or three, those left being near the anterior border, 
They may even disappear in the terminal scales. 
The typical feet bear the branchial process superiorly and 
three top-shaped ctenidia along the upper edge. The dorsal 
lobe is somewhat clavate, bevelled at the tip superiorly, with 
three terminal and two adjacent papilla (stylodes). The long 
dorsal bristles form a dense group, slender and finely tapered. 
They constitute a series of pencils, curved boldly upwards on 
each side. ‘They are very finely serrated, as in S. Jeffreysit. 
The ventral division of the foot is somewhat conical at the 
tip and has two smooth papillee—one springing from a broad 
process—near the point of the spine. ‘The upper ventral 
bristles (Pl. III. fig. 7) are two or three in number, the distal 
end of the shaft having nine or ten rows of spines, and a 
terminal piece tapering to a hair-like point and possessing 
nearly a dozen pseudo-articulations. ‘These tips are much 
shorter than the next in succession, which form a dense group 
of bristles with long shafts slightly enlarged at the end, and 
with a few (two or three) serrations in the upper examples, 
the rest being smooth. The tips are all very long (eighteen 
to twenty pseudo-articulations) and with a hair-like extremity. 
The next series possess a stronger and more distinctly curved 
shaft and a terminal piece of a single articulation, bifid at 
the tip and with a secondary piece, like a bird’s beak (Pl. ILI. 
fig. 8). The terminal pieces increase in length inferiorly, 
the last showing an indication of a second articulation towards 
the tip. It is in this row that the greatest divergence is 
noticed when contrasted with the Irish’ form (Sthenelais 
Jeffreysii, Mcl.), since several in the latter present three 
distinct articulations in the terminal piece. A membranous 
flap and a long papilla mark the next series, which have 
similar shafts, but their tips are tapering articulated processes 
ending in a hair-like extremity as in Leanira, Hach 
(Pl. LIL. fig. 9) has more than a dozen articulations. Lastly, 
from the special area ventrally spring a series with more 
slender shafts and five- to six-jointed terminal pieces ending 
in a minutely bifid tip (Pl. III. fig. 10). Internal to the 
subulate ventral cirrus 1s a top-shaped ctenidium. 
