Clare hi and Survey — ArchianncUJa and Polyehaela. 47 113 



segment. In the middle region there are 1 or 2 crochets in each dorsal 

 bundle; in the posterior region the number increases to 3. In the smaller 

 specimens there are only 3 or 4 capillary setae in each of the anterior dorsal 

 bundles. The number gradually decreases, the 15th-20th segments containing 

 1 or 2 capillary setae, and the posterior segments only a single capillary. 

 Crochets are present in all the ventral bundles — a character which distinguishes 

 this species from all others. In the anterior segments there are 5-7 crochets 

 in each bundle, accompanied by 2 very slender capillary setae (fig. 27b, c). 

 In the posterior segments each ventral bundle contains 3-5 crochets and 

 1 or 2 fine capillary setae. 



The crochets (figs. 27c, 27n) are distinctly bifid at the tip and boldly 

 curved. The shaft is constricted at the point where it emerges from the 

 skin. Above the constriction, on the posterior margin, is a delicate wing, a 

 structure which I have not noticed in any other Cirratulid. The dorsal setae 

 in each bundle are slightly thicker than the ventral ones. Passing backwards 

 the crochets gradually increase in size (compare figs. 27c and 27d), although 

 they still remain small as compared with C. setosa and C. zctlanclica. The 

 slender capillary setae (fig. 26b, c) which usually accompany the crochets, 

 both dorsally and ventrally, are frequently absent. 



This species is most nearly allied to Ohaetozone viridis (Langerhans), and 

 these two species are sharply separated from other species of the genus by 

 the structure and arrangement of the setae. The present species is 

 distinguished from G. viridis by the following characters : — (1) the presence 

 of crochets in all the ventral bundles (in C. viridis they are absent from the 

 two anterior bundles) ; (2) the shape of the crochets is somewhat different, 

 and the wing is absent in the setae of C. viridis ; (3) the presence of capillary 

 setae in all the ventral bundles. 



Habitat. — Blacksod Bay — A single specimen found in Laminaria roots 

 from Carrigeenmore. Ballynakill Haeboue — Taken on 

 two occasions, in the surface tow-net at night. 



Chaetozone killariensis sp. n. 



PL XII, figs. 28a-f. 



This species has only been found, up to the present, in Killary Harbour. 

 A number of specimens were obtained by washing the rich black mud, 

 dredged from the bottom of the harbour, through a fine silk net. Some of the 

 specimens contained immature eggs. The largest individual was 11 mm. in 

 length, and consisted of 84 setigerous segments. The body is widest in the 

 anterior third, tapering rapidly towards the head,. and very gradually towards 



I'KOC. E.I. A., VOL. XXXI, P 47 



