170 Prof. M'Intosh's Notes from the 



and somewhat spathulate process, one side of which bulges 

 move than the other immediately on expanding above the 

 shaft, whilst the tip is symmetrically narrowed to a blunt 

 point, which is cut into three spikes on each side, the centre 

 being produced as a long process with three lateral spikes 

 directed distally. In the examples from Luccomb Chine, Isle 

 of Wight, these lateral spikes are smaller and more numerous, 

 and the process is larger. Strise cross the flattened tip 

 from side to side, and are slightly curved upward at each 

 end, the bulged base of the tip often showing a differentia- 

 tion of these and a more marked curvature. The palete at 

 the extreme ends dorsally and ventrally are less neatly 

 formed than those in the centre of the semicircle, the inner 

 lateral spikes being long and powerful, whilst the central 

 elongated process is more or less rudimentary. All, how- 

 ever, have the asymmetrical base as in the other types of 

 the second and third rows. 



The second row consists of modified bristles with a slender 

 shaft tapering to a point at its base, and of a proportionally 

 massive tip shaped like a broad bill-hook. The shaft tapers 

 from its upper end to its pointed base and is comparatively 

 slender. It curves posteriorly into the convex margin of the 

 tip, whilst anteriorly it abruptly expands into a thin edge, 

 which is concave in its progress to the pointed tip. More- 

 over, a second outline occurs within the foregoing, so as to 

 simulate a double edge, as if a trace of a double wing were 

 present. The thin edge beyond the inner line is boldly 

 striated transversely throughout, and curved transverse 

 striae cross the greater part of the tip, but not the base. 



A considerable number of the bristles in this (second) row 

 present a further stage in the modification of the tip, which 

 forms a long, curved, tapering structure with the double 

 outline on the anterior face and the transverse strise through- 

 out the greater part of its extent. The two ridges on the 

 anterior face are evidently modifications of wings, and the 

 point is acute. The shaft is long and tapers from the upper 

 part to a point at the base, whilst the posterior curve comes 

 off distally before the anterior and is less abrupt. The 

 anterior outline swells into the " heel " of the tip and is 

 specially striated. In the St. Andrews forms these chiefly 

 occur at the ventral edge. In those from Luccomb Chine, 

 Isle of Wight, they occur all along the second or middle 

 series. 



In the variety ensifera from Lochmaddy and Guernsey 

 several of the paleae of the second row form long needle-like 

 processes projecting far beyond the rest, and giving a 



