CHATOZONE KILLARIENSIS. 491 
that it is most nearly allied to C. viridis, Langerhans, from which it is distinguished by the 
presence of hooks in all the ventral bundles (they are absent in C. wridis in the two anterior 
bundles); by the shape of the hooks, and, he says, the absence of a wing or hood in 
CO. viridis—a feature probably requiring further investigation ; and, lastly, by the presence 
of capillary bristles in all in the ventral series. 
CH@TOZONE KILLARIENSIS, Southern. Plate CXXXVI, fig. 13—bristle. 
Specific Characters—Head conical; no eyes. Dorsal tentacles in front of the first 
bristled segment, each of which has a lateral cirrus externally. Body 11 mm. long, and with 
eighty-four bristled segments ; widest in the anterior third, rapidly tapered anteriorly, and 
gradually so posteriorly, where it terminates in a dorsal anus with a ventral lobe beneath. 
Dorsal cirri fixed above the bristles. In the middle and anterior regions both dorsal and 
ventral divisions of the foot have only capillary bristles. Hooks appear ventrally in the fifty- 
sixth segment, and dorsally in the sixty-first. The dorsal hooks resemble short, flattened 
bristles with curved tips, and the uppermost dorsal hook is the largest. The main fang and 
the spike above are widely divergent. 
Synonym. 
1914. Chetozone Killariensis, Southern. Proc. Roy. Irish Acad., vol. xxxi, No. 47, p. 113, pl. xii, 
fio, 28 a—r. 
Habitat—A minute form (young?). Dredged in Killary Harbour in 7 fathoms, in 
rich, black mud (Southern). 
Head pointed. Body about 11 mm. in length, widest in the anterior third, tapering 
abruptly toward the head and more gradually to the tail, the anus being dorsal, with a 
smoothly rounded lobe beneath. Bristled segments eighty-four in the largest example. 
Dorsal tentacles on the segment in front of the first setigerous segment, and each is accom- 
panied externally by a lateral cirrus above the dorsal bristles. In the middle region both 
dorsal and ventral divisions of the foot have capillary bristles, the dorsal being longer than 
the ventral, long and short bristles, however, occurring in each tuft. The dorsal bristles 
(Plate CXXXVI, fig. 13) are longest between the twentieth and thirtieth segments, after 
which they gradually decrease in length. The shorter bristles anteriorly have a cylindrical 
shaft and a flattened tip, with a distinct curve at the junction. 
In the largest example the first ventral hook appears in the fifty-sixth segment, and the 
first dorsal in the sixty-first (Southern). In the caudal segments all the capillary bristles 
of the ventral bundle may be replaced by hooks. 
The dorsal hooks resemble the short capillary bristles in outline, except that the tip 
is curved and bifid, the upper hook in the dorsal division is much larger than the others 
in either division, and the upper in the ventral is similarly conspicuous. Most of the 
examples except one were immature. 
It resembles the young of Chetozone zetlandica, from which it differs in having no eyes, 
in having hooks in the posterior dorsal bundles, in the relative position, size and shape of 
the bristles, etc. (Southern). 
232 
