32 
PyramIpELLA.—Shell turreted; no epidermis: aperture entire, demi-oval ; outer lip sharp. 
Columella produced, subperforate at the base, and furnished with three trans- 
verse plaits. 
Plate XVI. Fig. 9. P. terebellum. 
SCALARIANA~_3 Genera. 
Shells without plaits on the columella; the margins of the aperture circularly united. 
Vermetus.—Shell thin, tubular, loosely spiral, adhering by the spire: aperture orbicu- 
lar, the margins united. An operculum. 
Plate XVI. Fig. 10. V. lumbricalis. 
ScaLarta.—Shell subturreted, ornamented with longitudinal, elevated, interrupted, near- 
ly acute ribs: aperture rounded, the margins circularly united, and terminated by 
a thin, recurved varix. 
Plate XVI. Fig. 11. S. pretiosa. (Turbo scalaris.—Linn.) 
Detpurnuta.—Shell subdiscoidal, or conical ;sumbilicated, solid; whorls rough or angu- 
lar: aperture entire, round, sometimes triangular; the margins united, mostly 
fringed or ventricose. 
Plate XVI. Fig. 12. D. laciniata. (Turbo delphinus.—Linn.) 
TURBINACEA.~—8 Genera. 
Shell turreted, or conoidal; the aperture round, or oblong, not effuse; the margins disunited. 
So.arrum.—Shell orbicular, depressed-conical, umbilicated, crenulated or dentated on 
the inner margin of the whorls: aperture nearly quadrangular. No columella. 
Plate XVI. Fig. 13, 13 (a). S. perspectivum. (Trochus perspectivus.—Linn.) 
Roretta.—Shell orbicular, shining, no epidermis; spire very short, sub-conoidal; lower 
surface convex and callous: aperture semicircular. 
Plate XVI. Fig. 14, 14 (a). R. lineolata. (Trochus vestiarius.— Linn.) 
Trocuus.—Shell conical; spire elevated, sometimes rather depressed; periphery more 
or less angular, often thin and sharp; aperture transversely depressed; the mar- 
gins disunited at the upper part; columella arched, more or less prominent at the 
base. An operculum. 
Plate XVI. Fig. 15. T. virgatus. (Idem.—Gmel.) 
Monoponta.—Shell oval or conoidal: aperture entire, round, the margins disunited at 
the upper part; columella arched, truncated at the base. An operculum. 
Plate XVI. Fig. 16. M. labio. ‘(Trochus labio——Linn.) 
T'urso.—Shell conoidal, or subturreted; the periphery never compressed: aperture 
entire, round, not modified by the penultimate whorl; the margins disunited at 
the upper part; columella arched, flattened, not truncated at the base. An 
operculum. 
Plate XVI. Fig, 17. T. pica. (Idem,—Linn.) 
