216 Proceedings of the Roual Irish Academfj. 



segments, and behind these a callus-shaped ring and at the hindmost 

 extremity a cup-shaped section. The ventral cirrus, which is the longest, 

 and the longer cirri, which are symmetrically arranged among the other 

 anal cini, have imdivided tips : the shorter intermediate cirri have a lobate 

 point. The anal cone, the anal papiQa of which is drawn out like a finger, 

 is low and Mes in the bottom of a funnel-like depression. The cephalic plate 

 has distinct glands, and the anterior segments distinct glandular bands. 

 The uneini of the first to the third setigerous segments are not particularly 

 strong, and lack bristles, and are, moreover, more or less ti'ansformed and 

 usually stand singly in each parapodium: the neck of the fully developed 

 uneini is inwardly distinctly constricted; the bristles join together uiujer 

 the big tooth. The anterior capillary setae have bordere that are either 

 faint or vanishing and a distinctly marked pencil of bristles. The posterior 

 capillary setae have quite narrow borders and smooth points. Tubes free, 

 straight, and rather thin. 



Cunningham and Eamage (1, p. 679) figvire, under the name of Axiothea 

 ratenata, a species which has not hitherto been at all well known. In an 

 earlier treatise (5, p. 220) I have considered the possibility that the authors 

 named have, in figuring the species in question, left out a segmental limit 

 somewhere just before the parapodia of the eighth setigerous segment, and 

 have thus foimd a certain resemblance to the Euclymene droeba.chiensis (Sars) 

 described in detail by me. In the Irish collection now under consideration, 

 however, I have certainly rediscovered Cunningham and Eamage's species, 

 which exhibits such very remarkable phenomena that I will not increase the 

 indefiniteness of the genus Eudymene Verrill by attributing the above species 

 to this genus, which is assuredly very indefinite in its range, but must for 

 this species establish the above-named new genus Caesicirrus. This new 

 genus, however, is quite certainly nearly related to Euclymene : in other 

 words, my diagnosis of Tribus Euclymenini must be widened so as to include 

 forms with a long eighth setigerous segment, having parapodia situated in 

 its hinder part. When I tried to define the Tribus named, no such form 

 was known ; in this connexion may be compared the species which I mentioned, 

 but did not name (5, p. 24-3), from East Greenland, which species seems to 

 lack a limit between the seventh and the eighth setigerous segment. That 

 species also, as I then took occasion to observe, falls outside the Tribus 

 Euclymenini as then defined by me, though it stands very near it of course. 

 Perhaps it may be closely related to the species now under discussion, since 

 its eighth setigerous s^ment seems to have more in common with the posterior 

 long segments than with the anterior short ones. 



The most tlistinctive characters of the genus Caesicirrus are plainly the 



