Gatty Marine Laboratory^ St. Andrews. 155 



crenate anus above it. Tlie colour varies from yellowish 

 orange to deep madder-brown. Two aclitetous segments 

 follow the prostomium. The fourth segment has a smaller 

 sessile foot than the succeeding segments and bears two 

 minute tufts of bristles which have the same structure as in 

 C. tentaculatus. It also carries a series of proportionally- 

 large filiform branchial cirri arranged in two lateral tufts, 

 each of seven or eight cirri of an orange colour, with con- 

 tained blood-vessels. These coil and twist during the 

 progress of the animal, and in proportion to the diameter of 

 the body have a larger bulk than those of C. tentaculatus. 



The following thirteen or fourteen segments bear branchial 

 cirri, each arising above and slightly behind a line through 

 the middle of the bristle-tuft. Some of these show a greater 

 amount of blood than those in the dense anterior tufts. 

 Here and there along the body a single cirrus springs from 

 the dorsal arch considerably above the bristles, but the 

 posterior region is devoid of them. On the whole, thes^ 

 cirri are much fewer in number than in C. tentaculatua , and 

 do not show the remarkable spiral coils so characteristic of 

 that species. 



The feet differ from those of C. tentaculatus in so far as 

 they are more prominent and the dorsal and ventral divisions 

 considerably closer — indeed, in some, e. ^. the first, the bases, 

 fused with the body-wall, closely approach. The first twelve 

 bristled segments have only the simple flattened tapering 

 bristles, the points being extremely slender, and the ventral 

 are distinguished from the dorsal by their shortness and in 

 some by their proportionally broader tips. The dorsal 

 slightly dilate from the base to the middle of the shaft, then 

 taper gradually to the very fine hair-like tip. Parasitic 

 structures, such as algae, abound on them, and render them 

 ])innate, besides winding round them. The front edge of 

 each bristle is minutely and regularly spinous, the direction 

 being distal. At the thirteenth foot a single crotchet appears 

 on the ventral division. In structure the crotchets (hooks) 

 dilate a little from the base to a point above the middle, 

 where there is a slight forward curve, then a slight backward 

 bend occurs, and again a forward curve to form the hook at 

 the tip. This projects through a neatly rounded aperture in 

 the cuticle, and is moderately acute in the uninjured forms. 

 In the sixteenth foot three hooks are present, and four in the 

 thirtieth. One or two bristles accompany the hooks. The 

 crotchets commence in the dorsal division about the thirtieth 

 foot, a slender sharp-pointed one appearing in the twenty- 

 ninth, or perhaps earlier, along with the bristles, and they 



