"The family Purpurifera is composed of genera taken chiefly from the large Linnæan genus Buccinum.
"It is thus divided:
"First, the genera with the canal ascending, or turned towards the back of the shell—
| Cassidaria, | } | Buccinum, helmets. |
| Cassis, |
"Cassidaria is not a very common genus; but the helmets, Cassis, are both numerous and plentiful in most collections. The straight aperture slightly reminds you of a Cypræa perhaps, but the short canal, abruptly turned back, is a clear distinction; the right-margin generally toothed; the columella folded, or wrinkled, transversely.
"C. cornuta, C. flummea, C. arèola and vibex, are all well-known species, C. cornuta has large tubercles like horns round the tip of the shell. C. arèola is marked with chequers. C. rufus, from the Moluccas, is a fine shell, with a deeply coloured red aperture.
"In the next division the canal is oblique, and directed backwards.
NASSA.
RICINULA.
PURPURA.