Gatli/ Marine Laboratory^ St. Awlrews. 177 



elevations vcntrally. Elovoii papillaj occur alon;^ 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 rcniform, the ante- 

 rior four being more or less rounded (PI. III. fig. (3). 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 somev/hat clavate, bevelled at the tip superiorly, with 

 three terminal and two adjacent papilhe (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. Jeffreysii. 

 The ventral division of the foot is somewhat conical at the 

 tip and has two smooth papillae — one springing from a broad 

 process — near the point of the spine. Tiie upper ventral 

 bristles (PI. III. fig. 7) are two or three in number, the distal 

 end of the shaft liaving nine or ten rows of spines, and a 

 terminal piece tapering to a hair-like point and possessing 

 nearly a dozen pseudo-articulations. Tiiese 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 (PI. III. 

 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^ McI.), 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. Each 

 (Ph III. 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 (PI. HI. fig, 10). Internal to the 

 subulate ventral cirrus is a top-shaped ctenidium. 



