188 PYGOSPIO. 



region is tapered, the comparative smoothness of the enlarged region behind, and the 

 tapering to the minute cirri at the tip of the tail, together with the numerous and narrow 

 segments — about two hundred — are features of moment. Few complete examples are 

 captured, so great is the facility for rupture. 



Colour. — Dorsum brownish-yellow, darker than usual in the group, marked by a 

 reddish stripe from the blood-vessel. Ventral surface dull yellow. 



The first foot has a small conical dorsal lamella directed obliquely upward, and a series 

 of somewhat short and finely tapered bristles. The ventral division is represented by a 

 small lobe, also conical, and a minute tuft of similar bristles. The second foot shows a 

 larger dorsal lamella, a larger tuft of bristles, the superior being the longer and more 

 slender, and a well-developed branchia. The ventral lamella is small and lanceolate, with 

 a tuft of minute, finely tapered bristles of the usual character. All the parts increase in 

 their progress backward. Thus at the tenth foot (Plate XCVIII, fig. 9 b) the branchia 

 forms an elongate massive cone with a double row of strong cilia. The upper lamella is 

 firm and of a broad slipper-shape or irregularly triangular, the point being dorsal and 

 the rounded heel ventral, and it is free from the branchia. A few long slender bristles 

 are uppermost, followed by the row of shorter forms. The ventral lamella is prominent 

 and conical, but the bristles are minute. 



The upper lamella is more elongated and more acute superiorly at the twentieth foot 

 (Plate XCVIII, fig. 9 c), but the bristles are unchanged, and the inferior lamella forms a 

 prominent cone. The appearance of the winged hooks (Plate OV, fig. 10 b) in the ventral 

 division seems to vary. Mesnil found they occurred between the thirty-second and thirty- 

 fifth bristled feet. In the examples from Lochmaddy, North Uist, such was the case, but 

 in those from Herm and Guernsey they appeared at the twenty-fifth bristled segment. 

 These winged hooks by-and-by also occur in the dorsal division (according to Mesnil, from 

 the thirty-fifth to the forty-second), and in those from Lochmaddy behind the fiftieth ; 

 the typical appearance in the middle of the body being shown in Plate XCVIII, fig. 9 d 

 (Herm). The winged hooks project considerably from the edge of the lamella, and are 

 thus frequently absent from preparations which have been much handled. They are 

 accompanied by the tapering capillary bristles, which do not show wings. 



Toward the posterior end the dorsal lamellae present a slight increase in size (Plate 

 XCVIII, fig. 9 e, and Plate C, fig. 7), being of a broadly lanceolate shape, whilst the 

 hooks and bristles, which are often broken, are of considerable strength. 



Habits. — An active form, coiling and wriggling in a vessel and forming inextricable 

 knots with its mobile body. 



Reproduction. — Female specimens procured in Herm and Guernsey in July and 

 August had numerous ova in the coelom, some of considerable size. 



Mesnil (1896) is inclined to link on Olaparede's Aonides auricidaris to this species, 

 and with reason ; and so with the Scolecolepis tenuis of Verrill. 



Genus CI. — Pygospio, Claparede, 1863. 



Prostomium without frontal processes. Two long tentacles. Branchiae commencing 

 a considerable distance backward. Vesicular pouches as in Polydora. Four anal cirri. 



