Gatty Marine Laboratory ^ St. Audi'ewx. 13 



hooks are accompanied by the short bristles with tlie spatu- 

 ]ate tips. The posterior hooks differ only in their smaller 

 size and the brevity of the base. In comparing the larger 

 with the smaller forms from Plymouth, the essential characters 

 of the bristles and hooks are as well shown by the smaller 

 as the larger. 



The tube is composed of a tough internal lining, coated 

 with fine sand-grains, the whole being firm and resistent, 

 especially in the Canadian examples. 



A form (BC), procured in numbers at Berehaven in 1886 

 by the Royal Irish Academy, appears to be a variety of 

 P. torelli, though presenting certain features of its own. 

 When the branchiae are absent the cephalic region presents 

 no deep fissure as in ordinary Sabellids, but the slight dorsal 

 furrow ends in a solid mass which, with an incurvation in 

 the middle, passes from side to side and then bounds the 

 region laterally to the ventral surface. This rim forms a 

 projecting base to the branchiije. The collar commences as 

 a narrow process on each side of the dorsal fissure, slopes 

 obliquely forward and outward, and inclines laterally and 

 ventrally into a deep though thin lamella, which attains its 

 maximum in the mid-ventral line, where it is separated from 

 its fellows by a fissure. The branchite preserve much of 

 their reddish-brown coloration in spirit, and they are of 

 considerable lenj^th. The pigment is arranged on the pinnte 

 so as to make a series of circular bands, as in S. peniciihis 

 and other forms, thus conferring great beauty on the ex- 

 panded organs. In some cases, when mounted, the reddish- 

 brown pigment is in isolated masses at intervals along the 

 filament, and patches occur on the terminal process. There 

 are about eleven filaments on each side, spiinging from the 

 central region of the cephalic plate — a basal fissure, most 

 distinct ventrally, occurring dorsally and ventraliy. They 

 are connected only at the base and are free throughout the 

 rest of their extent, and are long tapering organs with 

 proportionally short pinnae, which, as they reach the tip, 

 gradually diminish in length and end in a series of short 

 papillae at the base of the terminal strap-shaped tapering 

 process. The chordoid skeleton is continued along the 

 centre of the fiattened tip and into each pinna. In young 

 forms the pinnae are short, but the flattened terminal strap 

 is well developed. The budij is comparatively small, elon- 

 gated, and distinctly segmented from one end to the other — 

 a feature chai-acteristic of the species. Filty-six segments, 

 but the tail in the majority of the examples was in process of 

 reproduction, so that the actual number of segments must 



