66 Prof. M'liitosh's Notes from the 



after the median groove appears. The collar has a deep 

 dorsal fissure, and is formed much after the shape of that 

 of Chone reayi, viz., slopes a little forward from the dorsal 

 groove, and preserves au even outline throughout the rest 

 of its extent. It differs, however, in so far as the collar 

 forms a free edge dorsally on each side as far back as the 

 posterior border of tlie first segment. From tlie point of 

 attachment a promiueut ridge goes forwai'd on each side to 

 the pedicle of the branchiae, which does not project so far 

 forward as the collar. The edge of the collar throughout is 

 entire. The segments of the body are two-ringed, and there 

 are about sixty of them. 



The anterior region consists apparently of eight bristled 

 segments, but the bristles are inconspicuous, and the dorsal 

 furrow passes ventrally between the eighth and ninth 

 segments. Behind the collar is a single ring, then the 

 following segments are two-ringed. The anterior bristles 

 consist of an upper series (PI. II. fig, 13) with winged tips 

 finely tapered and a ventral series of spatulate forms 

 (PI. II. fig. 1^), the shafts of which are stouter and only 

 slightly tapered distally, the tip often having a filiform 

 process. 



The anterior hooks are comparatively short, have a some- 

 what long main fang (PL II. fig. 15), and six or seven 

 teeth on the crown behind it. The neck is short and 

 distinctly striated longitudinally, and the curve of the shaft 

 is marked as it tapers to the basal region. The posterior 

 hooks (PL III. fig. 15) have a main fang with a nearly 

 straight upper outline, and the six or seven teeth on the 

 crown behind it are slightly prominent. The posterior 

 curve is not quite straight superiorly, then bends nearly at a 

 right angle to the base. The anterior curve has a slight 

 prow and the outline of the base is sinuous. The tube is 

 formed chiefly of a firm, though brittle, secretion, with a 

 Foraminifer studded here and there on the surface. It 

 resembled that of Potamilla reniformis, but was less tough. 



It was at first thought probable that this was a northern 

 variety of Chone duneri or an allied form, but a consideration 

 of all the features negatived such a view. Though it is 

 known that the posterior (avicular) hooks of such forms 

 vary somewhat in the numl^er of visible teeth on the crown 

 above the main fang, yet the outline in each species has 

 certain limits in this respect. The peculiar structure of 

 the branchiae and the terminal processes in the present form 

 are also factors of importance. A fragmentary form pro- 

 cured by the 'Valorous' in 1875 in the Arctic sepas, has a 



