The fourth family, Buccinidæ, contains numerous genera, as examples of which we may instance Oliva, Harpa, Cassis, Purpura, Nassa, Terebra, Eburna, and Buccinum.
Oliva is so named from their resemblance in form to the olive. Their nearly cylindrical shell is slightly spiral, polished, and brilliant as the Cowries; its opening is still long and narrow, strongly notched in front, its edge columellar, swollen anteriorly into a kind of cushion, and striped obliquely in all its length.
Fig. 267. Oliva erythrostoma (Lamarck).
Fig. 268. Oliva porphyria (Linnæus).
Fig. 269. Oliva irisans (Lamarck).
Fig. 270. Oliva Peruviana (Lamarck).
These Molluscs belong to the seas of warm countries, where they frequent the sandy bottoms and clear waters. They creep about with much agility, reversing themselves quickly when they have been overturned; they live upon other animals, and are flesh-eaters. They are, in fact, taken at the Isle of Tranu by using flesh as bait. The colours of the shell are very varied, and sometimes fantastically streaked. Oliva erythrostoma (Fig. 267) is ornamented externally with flexual lines of a yellowish brown, with two brown bands, combined with the fine yellowish tint of gold colour within. Oliva porphyria, from the Brazil coast (Fig. 268), presents lines of a reddish brown, regularly interlaced with spotted large brown marks, upon a flesh-coloured ground. Oliva irisans (Fig. 269) is painted in zigzag lines, close and brown, edged with orange-yellow, and with two zones of darker brown, and reticulated. Oliva Peruviana (Fig. 270) is furrowed with regularly spaced bands.