47 142 Proceedings of the Royal Irish Academy. 



In a smaller specimen, 5 mm. long, the branchiae are proportionally much 

 longer, equalling the trunk in length. 



There are 26-28 setigerous segments, 8 thoracic and 18-20 abdominal. 

 The first and last segments bear no setae. The body is creamy-white, at 

 least in preserved specimens, and tapers somewhat abruptly towards the tail. 

 The segments are biannulate. 



There are 8 or 9 pairs of branched gills, and one pair of ventral unbranched 

 gills attached to the gill membrane. In addition there is an inner ring of 

 unbranched gills of varying number and length. The connecting membrane 

 runs up to the tip of the gills, the naked portion of which is intermediate in 

 length between those of 0. Duneri and C. infivndibuliformis (PI. XIV, 

 fig. 32 Ej. The connecting membrane is about two-thirds as high as the 

 filaments. The collar resembles that of C. iiifundibvliformis, but is not quite 

 so high and prominent. It is entire on the ventral side, is infolded dorsally, 

 and does not slope obliquely as in C. Duneri (figs. 32 A-c). 



The lip-membrane terminates on the ventral side in a bifid process 

 (figs. 32 B, c), which is absent in 0. infundihdiformis. 



The first setigerous segment is narrow, and bears only a dorsal bundle, 

 consisting of a row of long setae with narrow wings, and a row of short, 

 slender setae with only traces of wings. 



The second setigerous segment bears a row of glands behind the setae 

 (fig. 32a). This character has been noted in several species of Chone, 

 Euchone, and other Sabellidae, and also in Thclepidcs collaris and Tricho- 

 brancJms glo.cicdis. 



The thorax consists of one achaetous and eight setigerous segments. They 

 are biannulate, and longer than the abdominal segments, of which there are 

 19-21. The anal segment (fig. 32d) is achaetous. The anus is on the 

 ventral side. On the dorsal side of the anal segment is a long filiform 

 appendage which tapers to a fine point. It varies in length, but is generally 

 longer and thinner than is shown in fig. 32d. It closely resembles the anal 

 appendage of Jasminei/ra caudata Langerhans. 



There is a longitudinal median groove, which is dorsal in the thoracic, 

 ventral in the abdominal region, passing round from the ventral to the dorsal 

 side in the first abdominal segment. The margins of this groove, and also of 

 the intersegmental grooves, are lined by numerous gland cells (fig. 32d), which 

 are also present in a more diffused condition over the whole body. 



In the thoracic segments the dorsal bundles contain setae of three types. 

 In the upper part of the bundle there are 13 long, slender setae (fig. 32h), 

 with narrow striated wings. Beneath these are 14 setae with spatulate tips 

 (fig. 32f), which taper to a fine point much more gradually than those of 



