212 Proceediinis of fixe Royal Irish Academy. 



The area within the cirri does not appear to lie very deep, and is, moreover, 

 only slightly oblique. Xephridia occur in the sixth to the ninth setigerous 

 segments. 



Epidxrmcd Glands} — The anterior part as far as the fourth setigerous 

 segment is plentifully furnished with glands (fig. 19). Especially noticeable 

 are the rings in front of the parapodia,' and the glandular spots on the under- 

 side of the first setigerous segment, which occur as usual in a long-extending 

 form, but are here (because of some other system of preservation '{) faiut, and a 

 well-marked protracted glandular spot immediately within each nuchal organ, 

 and a smaller spot outside the foremost part of the same organ (fig. 17). On 

 the fomlh to the seventh setigerous segments chiefly are to be found anterior 

 glandular rings, which, however, decrease in strength backwards. On the 

 ventral side of the fifth to the eighth setigerous segments, immediately 

 beneath and in fi'ont of the lowest uncini, are to be found small and highly 

 characteristic round bundles of glands most distinctly on the sixth setigerous 

 segment (fig. 19). On the eighth and following setigerous segments, the glands 

 round the parapodia, and especially between those on the dorsal side, are 

 weak. Towards the posterior parts these glands increase, and gradually 

 (distinctly from about the twelfth setigerous segment) there appears a distinct 

 glandular ring in the hindmost part of the segment. It increases backwards, 

 and is found even on the hindmost segmeni, which is usually free from 

 setae (tig. 16). The outer side of the posterior cup-shaped section is to some 

 extent furnished with glands, especially towards the posterior parts, while the 

 inner side is only slightly provided with glands. Finally, such are entii-ely 

 lacking on the cirri and on the area within the cirri. 



Setae. — The spines on the foremost three setigerous segments are straight 

 and rather coarse (fig. 27). As a rule, they occur singly in each parapodimn ; 

 but double ones have sometimes been obser^'ed on either side of the second 

 and thkd setigerous segments. 



On the fourth setigerous segment begin the uncini, which here and on the 

 adjoining segments are moderately open (fig. 28). The number of uncini on 

 the fourth to the twentieth setigerous segments of a large indi\idual from 

 Howth, which has received special investigation in the matter of setae, is as 

 foUows : 4, 5, 7, 8, 12, 13, 16, 15, 14, 13, 12, 10, 12, 12, 12, 13, 14. Ou another 

 large individual the nineteenth to the twenty-second setigerous segments 

 have the following number of uncini: 15, 15, 16, 16. The number of teeth 



• AH observations about epidermal glands refer cxclusiTely to such as Lave been coloured M-ith 

 iodine green ; cf . Arwidsson {5) . 



^ In a number of individuals, probably those preserved in some other way, it is precisely the 

 glands on the posterior part of these segments that are most conspicuous, particularly on the under 

 side. 



