PROCLYMENE MULLERI. 309 



the low anal cone to the mid-ventral line, and outside the anal cone is another ring in the 

 preparation. 



The original description of the species by Sars (1851) is quite sufficient for its 

 discrimination. 



Arwidsson mentions that the fourth and fifth bristled segments are dotted with 

 yellowish-red points, and the sixth with more distinct touches. In a fragmentary example 

 from the Northumberland coast the mid-dorsal line has a distinct pink streak (from 

 the dorsal blood-vessel P). 



The first bristled segment is narrow and carries laterally a strong spine or two 

 and a tuft of short bristles near its anterior border. This spine has a striated central 

 region, increases in diameter from the base to the shoulder, and then diminishes to the 

 hard golden point. The second bristled segment is longer, has a fold toward its anterior 

 border behind which (fold) the spine or spines and bristles on each side are placed. They 

 thus are situated a little in front of the posterior boundary of the anterior third. The third 

 segment is slightly shorter, has its fold somewhat nearer the segment-junction and also 

 bears a spine or two and bristles on each side immediately behind the fold. The fourth 

 segment is similar in regard to the bristles and spines, and they are placed in the anterior 

 third. A change occurs in the fifth bristled segment, in which a short row of hooks is 

 found in a pit on the ventral surface on each side close behind the segment-junction, 

 and the same occurs in the sixth and seventh bristled segments. The eighth presents 

 elevated glandular ridges at the anterior border for the hooks, the bristle-tuft being at the 

 dorsal end, and so with the ninth segment. The tenth foot is somewhat peculiar in 

 position, appearing at what seems to be the segment-junction. The eleventh, however, is 

 clearly at the posterior end of the segment, which in this case coincided with the end of the 

 fragment. 



The bristles consist of a group of powerful golden capillary bristles (Plate CIX, 

 fig. 3) which have a nearly cylindrical shaft and a tapered tip with well-marked wings, 

 besides a few slender, translucent forms which taper terminally without traces of wings 

 (fig. 3 c, the anterior of Arwidsson). The hooks (Plate CIX. figs. 3 /; and 3 d), which com- 

 mence on the fifth bristled segment, are distinguished by their great size, the length and 

 curvature of the shaft which gradually dilates from the base to the slight shoulder from 

 which the long, straight, distal region or neck curves off, and as it again dilates a little 

 distally it is narrowest in the middle. The main fang passes off at more than a right 

 angle, and a knob occurs on the throat immediately below r , whilst on the crown are five 

 teeth, though all may not be visible. The gular bristles arise at the base of the great 

 fang and the sides of the knob, and slope, or rather curve, forward and upward. The 

 centre of the shaft is longitudinally striated, and the upper part of the neck is boldly 

 striated obliquely, the striae in the middle and lower part of the neck being less oblique. 

 Little difference is noticeable in the structure of the hooks, though in the first series one 

 or two may be imperfect. 



Arwidsson describes the tube as formed either of fine sand or of shell-fragments, 

 fragments of the spines of Echinus, Foraminifera, and larger sand-grains. 



Reproduction.— Arwidsson found in August a male and female with reproductive 

 elements fairly developed. 



