35 
ALATA — 3 Genera. 
Shell with a more or less elongated canal at the base of the aperture, the right lip of which changes 
its form with age, and has a sinus at the lower part. 
Rostellaria. — Shell fusiform or sub-turreted, terminated by a beak-shaped canal ; right 
lip entire or toothed, more or less dilated with age; with a sinus contiguous to 
the canal. 
Plate XVIII. Fig. 3. R. pes-pelicani. (Strombus pes-pelicani.— Linn.) 
Pterocera. — Shell ovate-oblong, ventricose, terminated at the lower part by an elon- 
gated canal : the right lip dilated by age into a digitated wing, with a sinus to- 
wards the base. Spire short. 
Plate XVIII. Fig. 4. P. aurantia. 
Strombus. — Shell ventricose, terminated at the base by a short, notched, or truncated 
canal: right lip dilated by age into a simple wing, lobed or crenated at the upper 
part, with a sinus at the lower part, separate from the canal or notch of the base. 
Plate XVIII. Fig. 5. S. auris Dianse. (Idem. — Linn.) 
PURPURIFERA.__.11 Genera. 
Shell with a short canal ascending posteriorly, or an oblique notch or demi-canal at the base of the 
aperture, directed towards the back. 
This Family is separated into Two Divisions. 
Division I. The canal ascenditig, or curved towards the hack. 
Cassidaria. — Shell sub-ovate or ovate-oblong: aperture longitudinal, narrow, termi- 
nated at the base by a curved, sub-ascending canal. Right lip varicose or repli- 
cate; left lip laid over the columella, mostly rough, granulated, tuberculated, or 
wrinkled. 
Plate XVIII. Fig. 6. C. thyrrena. (Buccinum thyrrenum. — Linn.) 
Cassis. — Shell inflated: aperture longitudinal, narrow, terminated at the base by a short 
canal, abruptly curved towards the back of the shell: columella plaited or trans- 
versely wrinkled. Right lip mostly toothed. 
(«) Spire having varices. 
Plate XVIII. Fig. 7. C. zebra. (Buccinum strigatum.— Gmel.) 
(6) Spire without varices. 
Plate XVIII. Fig. 7- («) C. testiculus. (Buccinum testiculus. — Linn.) 
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