40 Prof. M'Intosh's Notes from the 



head, which has a powerful main fang extending from the 

 throat at more than a right angle, and with five or more 

 smaller teeth on the crown in lateral view, and they extend 

 to the downward curve of the crown posteriorly. In con- 

 trasting these with the hooks of C. infundihuliformis, the 

 curvature is less, the neck shorter, and the crown somewhat 

 flatter. Moreover, whilst the body of the arctic specimen 

 is larger, the hooks are proportionally smaller. The hooks 

 in the seven rows maintain the same structure, the posterior, 

 perhaps, being slightly stronger. In transverse section of 

 the shaft of the hooks the centre is fibrous, and at the 

 shoulder it is somewhat flattened, with an indentation of 

 the fibrous area, a condition which explains the pecuHar 

 blank always seen on one side of the shaft. At the ninth 

 segment the hooks change to the dorsal side of the bristles, 

 and they maintain that position to the posterior end 

 of the body. These hooks are avicularian, and form a 

 single row, diminishing in size from the dorsal to the 

 ventral end adjoining the bristles. There are about thirty- 

 six hooks in each row anteriorly. Moreover, the hooks at 

 the upper end of the row have a larger base than those next 

 the bristles, for in the last hooks the base is in a line with 

 the neck and devoid of the anterior prow. In the upper 

 hooks the main fang is large and sharp, the anterior outline 

 below it deeply concave to the prow, after which it is nearly 

 straight. Pour distinct teeth occur above the main fang. 

 The posterior outline is irregular, a slight hollow occurring 

 at the neck, then a convexity from which a straight line 

 runs to the angle at the upper part of the base, another 

 straight line joining that bounding the free end. The base 

 and neck are boldly striated, the former transversely, the 

 latter longitudinally. At the lower end of the row the 

 posterior outline of the hook is nearly straight, only a 

 slight elevation occurring in the middle ; whilst the anterior 

 outline of the base is prolonged downward with a slight 

 posterior inclination, so that the hook has a base elongated 

 in the line of the neck. In some large forms from 

 St. Andrews these hooks were of a deep brown hue. 



In Chone infundibuliformis the hook in the middle of the 

 body considerably diverges from that of C. fauveli, since 

 the base is more massive ; the prow has a slight process 

 projecting downward, and the gulf below the acute main 

 fang, instead of having a nearly uniform outline on its 

 inner edge, has a distinct indentation, marking off, as it 

 were, the region of the prow. But the most divergent 

 feature is the crown, Avhich is flatttened and provided at its 



