BRANCHIOMMA VESICITLOSUM. 247 



bulging; the gulf between it and the great fang is small. The posterior outline is 

 straight, and a small remnant of the base posteriorly is present. The posterior hooks 

 (Plate CXXIX, fig. 3 e) agree in the general outline, but the process of the base is absent 

 posteriorly. It is this hook which Malmgren shows in his figure, unless the Arctic 

 species differs. In shape the hooks generally approach those of Euchone. The tube 

 is composed of secretion and mud, very little of the latter constituent occurring on a 

 third of the length at one end. 



Cunningham and damage (1888) state that they dredged an example on the Middle 

 Bank, Firth of Forth. Nothing more is mentioned. 



Genus CLXIV. — Branchiomma, Kolliker (Clap, revis.), 1858. 



Cephalic plate with a deep dorsal fissure ; collar has a distinct dorsal lamella separated 

 from the main part by a V-shaped notch; edges overlap at the fissure in the mid- 

 ventral line. Branchiae have a subulate terminal filament with a compound eye (minute 

 in some) on the inner edge. Tentacles (or palps) a pair. Mouth with lateral labial 

 processes. Body slightly flattened, tapering a little posteriorly, and ending in an anus. 

 Segments 100 — 120. Anterior region of eight to nine segments. Anterior bristles in two 

 groups,, upper with narrow wings, lower with broader wings. Posteriorly tips are much 

 elongated. Anterior hooks avicular with minute serrations on the main fang : accom- 

 panied by small penniform bristles. Posterior hooks similar but with shorter bases. 

 Tubes colonial, coriaceous internally ; externally with a coating of mud or fragments of 

 shells, gravel, zoophytes, algae and other growths. 



1. Bjranchiomma vesioulosum, Montagu, 1815. Plate CXV, figs. 2 and 2 a— body 

 and tube; Plate CXXVIII, figs. 4— 4/— bristles and hooks; Plate CXX, figs. 

 9 and 9a — anterior end and tip of branchia; Plate CXXXVIII, fig. 4 — tip of 

 branchial filament of var. B. Kollikeri. 



Specific Characters. — Cephalic plate with a deep fissure dorsalty, on each side of 

 which the somewhat deep white collar has a separate dorsal lamella, a V-shaped notch 

 separating it from the main part, which slopes downward and forward with an unbroken 

 edge to the mid-ventral line where the full and rounded edges overlap. Two eyes over 

 the brain. Branchiae of moderate length : filaments white externally, from eighteen to 

 twenty (thirty-two, Claparede), each ending in a subulate terminal process into which the 

 chordoid axis does not go, and often with an eye on the inner edge. Pinnae numerous, 

 very fine, of average length, and brownish-violet in colour, or with white bands. Some 

 are pale olive green with a band of white along the exterior of the filament. Others are 

 rose-pink with white specks; a few milk-white with a faint roseate hue (Brunotte). 



Body reaches 110 mm. or more; segments 100 — 120; slightly flattened, especially 

 posteriorly, where it is tapered and ends in an anus. Anterior region of nine segments, 

 eight of which are bristled ; dorsal groove passes between setigerous processes 8 and 9, 

 and reaches the mid-ventral line behind scute 9, from which it is continued to the tail. 

 Nine scutes in the anterior region, the first with a median dimple. Colour brown with 



