Gatty Marine hahoratory^ St. Andrews. 19 



where the scutes are somewhat broader and the median 

 groove is wider. The anterior region has nine segments 

 with a wider antero-posterior diameter than those which 

 follow^ whilst these, again, are wider than the caudal 

 segments. 



The colour of the body is dull orange or of a salmon hue, 

 universally and minutely dotted witli white grains. The 

 dorsal collar is pale, and is also minutely dotted with white 

 grains ventrally ; the flaps ai*e also pale with a brownish 

 edge — well marked in the anterior dimple of the fii'st shield. 

 The ventral scutes are paler, but also minutely dotted with 

 white, and the ventral groove is reddish. The cilia of the 

 dorsal end carry loose bodies actively forward. 



The bristles of the second region are arranged like the 

 inferior group in front, viz. with the long diameter of the 

 row vertical, and they spring from the tip in a double row- 

 that is, on each side of a ridge of tissue. The wings of 

 these are intermediate in character, being narrower than the 

 lower series and wider than the upper series of the fiist 

 region, Thair tips, however, are long, especially the upper 

 forms, and finely attenuate. The chief changes in the 

 bristles toward the tip of the tail are the shortening of the 

 shafts and the great elongation of the tips, which stretch from 

 the side of the flattened body as ilnely-tapered hairs. A 

 distinct curvature occurs at the commencement of the 

 wings. 



Neural canals occur from the second setigerons segment 

 backward. The segmental organs are found in the first, 

 second, and third setigerons segments, and they open by a 

 common canal. The anterior rows of hooks occupy the 

 summit of the rounded ridge, which begins close to the 

 setigerons process and passes ventrally near the scute. Each 

 hook is avicular in shape, with a marked forward curvature 

 of the posterior outline at the crown, a poweif ul and sharp 

 main fang with a series of very minute serrations above it, 

 a neck of moderate length, and a long tap;ring base. Bold 

 striae pass from the crown to the base, into which thev 

 curve a little behind the prow. Each hook is accompanied by 

 a short broad bristle, with a spatulate tip bent at an angle and 

 ending in a point, or when seen obliquely the tip is hastate, 

 or on edge a hook-like organ. In a specimen from South 

 Devon in the British Museum, both these and the hooks 

 had their " heads " tinted brown. Tlie posterior hoo!;s are 

 smaller, with a shorter neck and shorter base, and more 

 distinct serrations above the main fang. The tube is 

 leathery, coated extcrnallv with coarse sand minulrd with 



2* 



