196 SYLLIS BREVICIRRATA. 



was occupied by an opaque bud distended with male elements, and much more bulky than 

 the caudal region of the adult in front. 



The foot (Plate LXX, fig. 19) anteriorly shows a somewhat stout tapered cirrus of 

 about seventeen segments. The setigerous region is rather narrow and elongate when 

 seen from above, obliquely conical in lateral view. The two spines, which have a blunt 

 tip, pierce the upper angle. Next these are two bristles much longer than the others, 

 and apparently devoid of terminal pieces. The group of smaller bristles of the average size 

 beneath show short tips with a simple hook and a spinous edge (Plate LXXXIV, fig. 6). 

 The ventral cirrus is narrow and elongate, but does not reach the tip of the setigerous 

 region. 



The bud was nearly ready for separation. The foot (Plate LXX, fig. 19 a) has a dorsal 

 cirrus of about thirteen articulations with a tuft of slender, tapering, swimming-bristles 

 beneath. The setigerous region has a similar outline to that of the nurse- stock, the spines 

 end in a probe-tip; the two upper bristles are larger and devoid of terminal pieces, and the 

 inferior bristles correspond with those in the adult. The ventral cirrus is also similar. 



This species presents an intermediate condition to that of Syllis gracilis and Syllis 

 sjpongicola, in which a further differentiation of the tip of the shaft of the enlarged bristles 

 occurs. Subsequent investigation may show a closer relationship with either of these than 

 at present can be made out. The occurrence of these enlarged bristles anteriorly is 

 noteworthy. 



6. Syllis breviclkrata, n. s. Plate LXX, fig. 20 — foot; Plate LXXIX, figs. 14 and 



14 a — bristles. 



Specific Characters. — Head resembling that of Syllis gracilis. Foot with a short 

 dorsal cirrus of about nine segments. Setigerous region bluntly conical, the tips of the 

 spines slightly dilated and bevelled. Bristles stout, terminal pieces comparatively short, 

 with a spinous edge and a simple hook at the tip. Ventral cirrus tongue-shaped, scarcely 

 projecting so far as the tip of the setigerous region. 



Habitat. — Between tide-marks, Herm, August, 1868. 



Head apparently similar to that of Syllis gracilis. 



Body about three eighths of an inch in length, tapered to a delicate tail furnished 

 with two caudal cirri posteriorly, but only slightly diminished towards the head. The 

 colour has disappeared. 



The foot (Plate LXX, fig. 20) has a short and rather thick dorsal cirrus of about 

 nine segments. The setigerous region is bluntly conical with the tips of the spines, which 

 are slightly dilated and bevelled, projecting at the upper angle. The bristles (Plate 

 LXXIX, figs. 14 and 14 a) are somewhat stout, with curved shafts and dilated and 

 bevelled tips. The terminal pieces are comparatively short and have a simple hook at the 

 tip with a spinous edge below. The tongue-shaped ventral cirrus scarcely projects so far 

 as the tip of the setigerous lobe, and thus is shorter than in S. gracilis. 



Posteriorly the same type of bristle is found in the feet, but further examination 

 may show that certain sexual forms of S. gracilis, to which this form is evidently allied, 

 may vary in this respect. 



