222 Proceedings of the Royal Irish Academy. 



individuals there can be seen a strongly marked glandular ring near the edge 

 of the cup-shaped section ; the inside thereof, like the inside of the cirri, 

 lacks glands. 



Setae. — The following notes on the setae are, for the most part, based on 

 the two largest individuals. 



The uncini on the first to the third setigerous segments are usually single 

 in each parapodium. In some individuals, however, two uncini have been 

 observed on one side of the third setigerous segment. These uncini are very 

 strongly transformed ; they have the great tooth, especially on the first 

 setigerous segment, only slightly bent, lack bristles, and possess a highly 

 thickened proximal portion (figs. 20-21). The number of the teeth is 3', 4*''. 

 Under the great tooth there is on the very first setigerous segment a distinct 

 little boss, corresponding to the attachment for the bristles in the developed 

 ruicini ; like the bent form of the great tooth, the boss increases on the two 

 following segments. 



So early as on the fourth setigerous segment there are fully developed 

 uncini, all with bristles ; the topmost uncini of the segment, on the other 

 hand, have the great tooth rather blunt -headed (fig. 22). Moreover the uncini 

 on the more anterior of these segments are more faintly developed in their 

 outer part ; posteriorly, they acquire an outer part which is greatly 

 extended, and in comparison with the inner portion considerable. The 

 attachment of the bristles forms against the base of the great tooth a little circle 

 which is extremely characteristic in shape (fig. 25). The number of the uncini 

 on setigerous segments 4-19 of the large complete individual is : 9, 9, 10, 11, 

 12, 12, 14, 14, 14, 14, 13, 11, 10, 10, 6, 5— the last two segments not being 

 completely regenerated. Number of teeth is 5*"^ 6"-'^ 5-6'*"". One individual, 

 whose anterior region, as far as the eighth setigerous segment inclusive, 

 attains a length of 10'5 mm, possesses on these segments the following number 

 of uncini: 1, 1, 1, 7, 7, 7, 8, 9. 



The anterior capillaiy setae have faint borders which towards the hinder 

 parts of the body almost disappear. The point of these setae is long ; from 

 the tenth setigerous segment onwards the point bears a very distinct pencil of 

 bristles (fig. 26), which is broadest (c. 14 /u) near the base, where it does not 

 always finish off simultaneously on both sides. On the seventh setigerous 

 segment the pencil of bristles is rather faint, and further forward it disappears 

 all but completely ; but nevertheless traces of it have been observed on the third 

 and on the second setigerous segments. On the eighth and ninth setigerous 

 segments this pencil of bristles is excessively fine, extended, and of even 

 breadth ; its breadth in the case of large individuals is only about 4 ^u. At the 

 same time the number of anterior capillary setae on these two segments is 



