OIERATULUS TENTACULATUS. 245 



process. Such, perhaps, may be connected with injuries and reproduction. The number 

 of segments is 300 or upward in a large example. 



Colour of a dull yellowish-orange in front, and dull yellow behind, the long tentacles 

 being orange, whilst the blood-vessels give streaks of red to the various parts. Some 

 show vertical lines of dark pigment in the sulci at the segment-junctions from the fourth 

 segment backward for some distance. 



On an elevated ridge which lies dorsally between the fifth and sixth bristled segments 

 is a dense mass of tentacles on each side. In shape the elevation is somewhat crescentic 

 in front, straight behind, and the cluster of tentacles numbers at least twenty. 



Each segment behind the foregoing has laterally its branchia situated behind and 

 rather above the level of the upper bristle-tuft, and this throughout the whole anterior 

 region — to the number of about 100 — at least in large examples. The branchiaB are more 

 scattered in the middle and posterior regions, and cease altogether about the thirty-fifth 

 or fortieth from the tip of the tail. After the seventh or eighth the bristled segments are 

 very narrow for a considerable distance, then become slightly wider, and again toward 

 the tip of the tail are very narrow (Plate XCII, fig. 1, and Plate XCVIII, fig. 18). 



The remarkable spiral coils of these organs constitute a feature of the species. They 

 have no cilia, and contact with pure sea- water is less congenial to the animal than mud, 

 which at least enables it to separate the long, coiled structures. Claparede mentions the 

 occurrence of cilia on these organs in C. chrysoderma. 



The peristomial segment is somewhat narrower than the two which follow, each 

 of which has various transverse creases or wrinkles. These three are devoid of bristles, 

 hooks, or other appendages. 



The first setigerous segment succeeds the foregoing, and is broader than its successors. 

 The foot is represented in the lateral region only by dorsal and ventral setigerous pro- 

 cesses, which bear tufts of capillary bristles; moreover, near the junction with the 

 segment behind, and almost on a level with the upper bristles, is a long coiled branchia. 

 The capillary bristles (Plate OVTI, fig. 1) have somewhat stout shafts and long, flattened, 

 tapering tips with a narrow web of spines directed distally. The figure given by 

 De St. Joseph (' Ann. Sci. nat.,' 8 e ser., xvii, pi. iii, fig. 53) is only diagrammatic. These 

 bristles have a uniform translucent aspect, and the flattening is evident when twisted. 

 They are slightly tapered toward the base, whilst the tips are very delicate. Faint 

 transverse wrinkles occur at the base and for a short distance above it. 



The four or five bristled segments which succeed are broader than those next them, 

 but all have the capillary bristles dorsally and ventrally. In the groove between the 

 second and third bristled segment a second and smaller branchia occurs, the base arising 

 a little above the level of the dorsal bristle-tuft, and so with the following segments, viz. 

 in the groove between the third and as far as the sixth. 



The branchias and tentacles vary in size according to the degree of development, 

 those in process of reproduction being often very small, whilst the older examples are 

 thick. All are minutely ringed, probably from the muscular fibres. 



The strong hooks (Plate CVII, fig. 1 a) commence in the large examples from 

 Plymouth in the ventral series at the sixty-second bristled segment (sixtieth to 

 sixty-fifth in others). They are at first slender, but soon become robust. The 



