358 SERPULA VERMICULARIS. 
1913. Serpula vermicularis, Khlers. Deut. Stidpol. Hxped., p. 581. 
1914. es 5 Southern. Proc. Roy. Ivish Acad., vol. xxxi, No. 47, p. 146. 
- 5, x Fauvel. Campag. Scient. Monaco, xlvi, p. 320, pl. xxxi, fig. 24. 
1915. ks J Allen. Journ. M. B. A., vol. x, p. 648. 
_ * a Southern. Irish Se. Invest., No. 3 p. 49. 
1917. - ns Rioja. Anél. Polig. Cantab., p. 73. 
1918. 7 Fe Johansson. Kungl. Svensk. Vetensk. Handl., Bd. lvin, No. 7, p. 6. 
1920. a - Pixell. Scott. Antarct. Exped., vol. vu, p. 88. 
- E , Chamberlin. Canad. Arctic. Exped., 1913-18, vol. ix, pt. B, p. 27. 
1921. re - Benham. Austral. Antarct. Exped., vol. vi, pt. i, p. 112. 
Habitat —Not uncommon in the coralline region all round the British shores. Berwick 
Bay (Johnston) ; Polperro (Laughrin) ; Falmouth and Exmouth (W. P. Cocks) ; 60 fathoms 
9 miles off Balta, Shetland (J. G. J.); ‘Knight Errant,” 96 metres off N. Rona. Plymouth 
(Spence Bate and B. Rowe, Allen, Crawshay) ; Torquay (Elwes); Firth of Forth (Leslie 
and Herdman) ; West Coast of Ireland (Southern). 
The Southern examples, e.g., from Falmouth and Exmouth, are often in massive groups 
of aggregated tubes attached to pectens, oysters, and other bivalves. 
Cosmopolitan, ranging almost from pole to pole. At Cape Bojeador (Ehlers) ; shores 
of Cantabria (Rioja); Adriatic (Marenzeller); Australia (Johansson); Magellan (Hhlers) ; 
Kerguelen (Marion) ; shores of France (Fauvel, etc.). Extensively distributed in the North 
Sea and the Atlantic; Mediterranean (Panceri, etc.); Sweden (Malmgren); Adriatic 
(Grube), and Hastern Mediterranean (Marenzeller); Madeira (Langerhans); Antarctic 
regions (Scott. Hxped., Pixell: German Exped., Ehlers; French Exped., Gravier). 
Dorsally the edge of the alar membrane is continuous with the collar on each side—a 
considerable gap, however, intervening between the points of attachment. The collar then 
passes on each side as a deep, frilled lamella to the mid-ventral line, where it is continuous 
with that of the opposite side. The mouth opens between the branchial fans nearer the 
ventral than the dorsal border; dorsally it has the ciliated upper lip, and ventrally the 
ciliated lower lip, whilst below is a triangular area. 
The branchize, the filaments of which are from thirty to thirty-two on each side, form 
two fans of moderate length, and are tinted of a fine red hue near the tip. Each filament 
tapers toward the extremity, and ends in a long tapering process (Plate CX XI, fig. 7a). The 
cuticle is thick, and the longitudinal and circujar muscles well developed, but no chordoid 
skeleton is present. The pinne are of moderate length, the longest beg about a third 
from the tip, and they taper from base to apex, and likewise show no chordoid skeleton. 
Their colour is variable, reddish with white bars, entirely red or white, with darker zones ; 
sometimes the base is red and the rest white. The pinne take their hue from the bars 
of colour of the region to which they are fixed. In very young examples the base is red, 
and the filaments greenish from the blood. 
The opercula spring from the dorsal edge of the branchial fans, that on the one side being 
short and rudimentary, whilst that on the other forms a finely fluted vase supported on a 
stalk, which gradually expands as it passes upward to the fiuted cup (Plate CXXI, fig. 7), 
which has from fifty to one hundred or more denticulations. In many cases the functional 
operculum is on the left, in others on the right. The distal cup 1s hollowed and comparatively 
