Clare Island Survey — Arcldannelida and Polychaeta. 47 29 



thick spines with swollen truncated tips (fig. 4e, a). The dorsal simple seta 

 is curved at the distal end, where it terminates in a point which is delicately 

 winged, and serrated on the convex side (fig. 4e, b). The compound setae 

 are short and thick, the swollen tips of the shafts ending in 3 or 4 blunt teeth. 

 The terminal pieces are distinctly bifid at the tip, 7 being short and 2 long 

 (fig. 4e, c and d). The edge of the long tips is coarsely serrated. In the 

 succeeding segments the distinction between the setae with short and long 

 terminal pieces disappears, and there is a gradual transition from the long 

 dorsal to the short ventral tips. Taking the 16th foot as typical of this 

 region (fig. 4d), it is seen that the setigerous lobe is more elongate, the spine 

 is very slender (fig. 4f, a), resembling that of the first segment, and less than 

 half as thick as the spines in segments 2-6. The dorsal simple seta is similar, 

 except that the delicate wing at the tip is cup-shaped ; but this may be due 

 to abrasion (fig. 4f, b). The compound setae are much longer and thinner 

 (fig. 4f, c and d), with distinctly bifid terminal pieces and serrated edges, the 

 length of the terminal pieces decreasing from above downwards. In the last 

 3 or 4 segments there is in addition a very slender simple seta in the ventral 

 part of the foot. In the dorsal region of the middle and posterior feet 

 there are two very slender spines (fig. 4d). These may be the forerunners of 

 the swimming setae which develop at maturity. 



The dorsal cirri of all the feet are long and cylindrical, with no indications 

 of the moniliform condition. The ventral cirri are also very long, increasing 

 in size from in front backwards. They are placed towards the extremity of 

 the setigerous lobes, and extend outwards beyond the setae. The great 

 length of the ventral cirri seems to be a character of the genus Streptosyllis. 



The pharynx (fig. 4a) is short, straight, and broad, without a tooth, 

 extending through 3 segments. It has 8 papillae in front. The proventri- 

 culus is massive, extending through 6 segments, and has 48 rows of glands. 



None of the specimens are mature ; but an immature female has eggs 

 beginning in the 12th segment. 



Webster and Benedict do not state the number of segments in the 

 anterior region of the body. The present species differs from S. arcnac in 

 many respects, especially in the shape of the setae, which have simple winged 

 tips. S. varians differs from the present species in the length of the proboscis 

 and proventriculus, in having some of the dorsal cirri moniliform, in the larger 

 palps, and in the minute structure of the setae, and in the much greater 

 number of anterior segments with thick spines. From <S'. Wcbstcri this species 

 differs in having six segments in the anterior region, as against five, and in the 

 structure of the setae. 



Habitat.— Clew Bay — Dredged in 24fms., on a bottom of sand and shells. 



