Clare Island Survey — Archiannelida and Polychaeta. 47 31 



it bears a sharp lateral tooth (PL IV, figs. 6a, 6e). The proventriculus is long 

 and cylindrical, equal in length to the pharynx, and occupying 11 segments. 

 It has about 45 rows of glands, which are joined by wavy lines. Behind it 

 passes into the broad intestine, which has two diverticula in front, closely 

 pressed against the posterior part of the proventriculus. 



The anterior parapodia (PI. IV, fig. 6c) have bluntly rounded, bifid seti- 

 gerous lobes. The dorsal cirrus is long and cylindrical, indistinctly jointed 

 at the base. The ventral cirrus is massive, swollen at the base, and projects 

 beyond the setigerous lobe. The thirteenth setigerous segment contained a 

 fan- shaped series of 18 setae, all very similar in shape. The shafts are 

 slightly curved, swollen and bevelled at the tip, with a distinct shoulder, and 

 a series of spines on the upper edge. The terminal pieces do not differ much 

 in size, those in the middle of the foot being slightly longer than the others. 

 They end in a simple boldly curved tip (PI. IV, fig. 6f, h) and the whole, 

 except the extreme point, is enveloped in a delicate sheath. Pig. 6f, c shows 

 one of the terminal pieces in side-view. The spines are large and thick, with 

 peculiarly swollen truncated tips (PI. IV, figs. 6c, 6f, a). The anterior 15 

 segments have these large spines. They gradually increase in size up to the 

 10th segment. Prom the 16th segment onwards they are replaced by slender 

 spines, one in each foot, of a similar shape, except for the fact that the 

 swollen tip gradually becomes less prominent ; and in the 23rd segment they 

 are only bluntly pointed (PL IV, fig. 6g, a). Segments 1-13 have two spines 

 in each foot, and the remaining segments a single spine in each foot. In 

 the 24th segment a simple dorsal seta appears (PL IV, fig. 6g, c), and is 

 present in the remaining feet. It is curved and winged at the distal end, 

 indistinctly bifid at the tip, and minutely serrate on the convex margin. 



Capillary swimming setae commence on the 31st segment, though the 

 feet are modified and dorsal spines present on the 29th foot. In the middle 

 region of the body, the foot (PL IV, fig. 6d) is biramous, the dorsal branch 

 having a bunch of long capillary setae embedded in a shallow sac in the foot, 

 and a slender spine with a bluntly rounded tip. The dorsal and ventral cirri 

 resemble those in the anterior feet, but are smaller in proportion. The ventral 

 division of the foot bears a single dorsal simple winged seta, 4 or 5 compound 

 setae, and a simple ventral seta (PL IV, fig. 6g, d) differing from the 

 dorsal one in the absence of the wing and serrations. The spine is similar to 

 that of the dorsal division of the foot. The compound setae resemble closely 

 those in the anterior segments, though the terminal hook is more boldly 

 defined. 



This species agrees with Opisthodonta morena Langerhans, in the position 

 of the tooth in the pharynx, and the smooth tentacles and cirri, but in other 



