126 CEMETOPTERUS VARIOPEDATUS. 



differ from those in front for they Lave eleven or twelve teeth (Plate CII, figs. 

 hj and 5 k). 



It is in this region, viz. the eleventh segment, that the cylindrical faecal masses first 

 appear, so that they must be formed in front of it. The inner surface of the gut is here 

 thrown into a complex series of folds or large villi, but no evidence of the method by 

 which these faecal masses are formed is visible. 



In a living example from St. Andrews, kindly brought by one of the fishermen, 

 the three great lamellae on the dorsum of the middle region of the body are waved to and 

 fro as if performing a respiratory function, either for blood or coelomic fluid. The 

 tentacles are also slowly waved to and fro, now stretched a little and now contracted. 

 The muscularity of the three great lamellae is considerable, and they move with a 

 vigorous fanning motion from front to rear. Waves of what seem to be coelomic fluid 

 distend these organs in a somewhat regular manner, so that the movements may be 

 respiratory. 



The general colour is dull yellow, deepest on the first region of the body, which also 

 presents a faint madder-brown tinge along the oral flap in front. The two greatly 

 modified feet, which pass forward as dorsal fans, represent the dorsal division of the 

 tenth bristled foot. Below the ninth a pale flap on each side passes inward toward the 

 middle line, a gap moreover separating it from its neighbour. It bears a border of hooks 

 and probably corresponds to the ventral division. The pair below the alar dorsal processes 

 which next follow, unite by their anterior border in the middle line, which is frilled, and 

 their outer border bends round and joins its fellow also, so that a hollow flap or basin is 

 formed with the hooks as a margin all round. A tendency to a median separation is 

 indicated by a depressed part in front and rear. The next ventral flap has a similar 

 arrangement only it is larger. On the dorsum above these are the dark greyish folds of 

 the crenated gut, which in the specimen were interrupted by a bilobed pale fold con- 

 tinuous laterally with the second ventral flaps just mentioned. Between this and the 

 next process is a brown median line on the ventral surface. The next ventral flaps are 

 smaller and differently arranged, projecting ventrally as free bifid lamellae continuous at 

 each side with the first great median dorsal flap. The posterior wall of the flap is dis- 

 tended by a greyish mass as if the gut communicated with it, but whether from rupture 

 or otherwise is undetermined. The margins of these three great dorsal lamellae can be 

 crenated in contraction. Massive bifid ventral flaps occur on the second and third 

 lamellae, and their prominent margins bear the hooks. 



The next segment has dorsally a pair of long and slightly curved lanceolate lamellae 

 tapered toward the tip, and having the bristles internally. They would thus correspond 

 to the dorsal division of the foot. The inner edge is connate with that of the opposite 

 side. The ventral division seems to be split into two, the upper forms a lanceolate 

 process attached to the base of the former, and with a line of golden hooks inferiorly; 

 the lower forms the ventral flap also with its line of hooks ; and so on the other side, the 

 processes being double. There are apparently fifteen segments posteriorly bearing these 

 processes, besides the terminal pair, also having bristles, on each side of the dorsal 

 anus. The dorsal processes are large and prominent in the anterior part of this 

 region, diminish gradually to shorter and narrower lamellae, which, however, preserve 



