SYLLIS ABYSSICOLA. 207 



or more segments. Setigerous region conical. Bristles strong, translucent, with 

 indications of serrations on the distal dilatation of the shaft. Terminal piece of 

 moderate length, with a simple hook at the end, and just below it the spinous edge ends 

 in a somewhat stronger spike, so that a pseudo-bifid aspect is produced. Ventral cirrus 

 elongate ovate or broadly lanceolate, and does not reach the tip of the setigerous region. 



Habitat. — Under stones between tide-marks, at Guernsey and Herm. 



Head apparently typical, with large frontal palpi, but the eyes had disappeared before 

 a critical examination was made. 



Body of comparatively large size and 1-J- in. in length, the general aspect being that 

 of Syllis armillaris. The tail in all is incomplete. 



The foot (Plate LXX, fig. 23) presents dorsally a comparatively long articulated cirrus, 

 having twenty-four to twenty-eight or more segments. The setigerous region is conical, with 

 the spines piercing the upper angle. The bristles (Plate LXXIX, figs. 18, 18 a) are strong, 

 translucent, and with the usual curve towards the dilated end of the shaft. The con- 

 vexity of the dilatation has indications of serrations. The terminal piece is of moderate 

 length with a hook at the tip, and just below it another minute tooth at the end of the 

 spinous edge. The latter tooth is easily overlooked. 



The ventral lobe is elongate-ovate or broadly lanceolate, and does not reach the tip of 

 the setigerous region. It is somewhat diminished posteriorly. 



Posteriorly the body has many large ova, and a developing tuft of simple swimming- 

 bristles appears between the cirrus and the setigerous region. A bud was thus forming. 

 In this region the cirrus is shorter, about a dozen articulations only being present. 



This species somewhat approaches Tyjpanosyllis zebra, but is readily distinguished 

 from it by the colouration, and the structure of the foot and bristles, the terminal pieces 

 being shorter and broader proportionately, and the secondary process beneath the terminal 

 hook is closer to the latter and more minute. 



11. Syllis abyssicola, Elders, 1875. Fig. 55. 



Specific Characters. — Head somewhat triangular, bluntly pointed anteriorly, with 

 elongate-ovoid palps. Lateral tentacles of fourteen segments; median of seventeen segments. 

 No eyes. Body deep yellow : first segment very short, with a pair of cirri on each side, 

 the dorsal with thirteen segments. Proboscis has ten papillae, and a single tooth behind 

 them. Foot has dorsally a cirrus of nine to eleven segments ; setigerous region cylindrical ; 

 two or three of the upper bristles have long tapering tips with a simple hook. The lower 

 bristles have much shorter tips. Ventral cirrus is somewhat cylindrical and pointed. 



Synonyms. 



1875. Syllis abyssicola, Ehlers. Zeitsch. f. w. Zool., Bd. xxv, p. 45, Taf. ii, f. 18—20. 

 1879. Ehlersia „ Langerhans. Ibid., Bd. xxxii, p. 237. 



Habitat— Dredged at Station 30, 56° 24' X., 11° 37' W., in the < Porcupine' Expedi- 

 tion of 1869, at a depth of 1380 fathoms amongst dark-coloured mud. Langerhans says 

 1483 fathoms. 



