72 Lamarck’s Genera of Shells. 
extremity. Operculum pedunculated, flat at top, situated be- 
tween the branchie. 
Tube testaceous, twisted into an orbicular discoidal spire; 
lower surface flat, fixed. 
Type. Spirorbis nautiloides* (Serpula spirorbis. Linn.) 
Shell discoidal, subumbilicate ; the whorls rounded above, 
smooth, somewhat wrinkled. The Sea, on Fusi. Pl. iii. Fig. 7. 
6 Species. 
2. Serpula. 
Body tubular, elongated, rather depressed, posteriorly at- 
tenuated; with numerous narrow segments. A single row of 
small bundles of awl-shaped and crooked sete on each side. 
Two terminal fan-shaped branchie, each deeply and finely 
digitated ; digitations plumose ; mouth terminal, between the 
branchiz, surmounted by a pedunculated operculum, funnel or 
club-shaped. Tubes solid, calcareous, irregularly twisted, 
grouped or solitary, fixed ; aperture terminal, round, very simple. 
Type. Serpula vermicularis. (Idem. Linn.) 
Shell creeping, tapering, curved, not spiral, sometimes slightly 
keeled. PI. iii. Fig. 8.. European Ocean. 26 Species. 
3. Vermilia tT. 
Body tubular, elongated, posteriorly attenuated; with an 
external, testaceous, orbicular, simple operculum. 
Tube testaceous, cylindrical, gradually attenuated posteri- 
orly, more or less contorted, fixed laterally to marine bodies. 
Aperture round, border with from one to three teeth. 
Type. Vermilia rostrata t. 
Shell tapering, smooth, incrusted with madrepores ; aperture 
with one sharp beak-shaped tooth. New Holland. 8 Species. 
4, Galeolaria §. 
Body tubular, with a compound testaceous operculum on the 
fore part. 
Tubes testaceous, very numerous, cylindrical, sub-angular, 
straight-wavy, crowded, matted together, fixed by the base, 
open at the summit. Aperture orbicular, margin terminating 
* Nautilus-like, + From vermis, a worm, 
$ Rostrwn, a beak. § Galea, a helmet. 
