Fig. 282. Harpa ventricosa (Lamarck).
The Harpas are shells of the Indian Ocean, richly enamelled within, and ornamented externally with slightly oblique longitudinal stripes in gay colours, with finely-sculptured forms in the intervals; spiral very small, and opening large. Among the more attractive species are Harpa ventricosa (Fig. 282), Harpa imperialis (Fig. 283), and Harpa articularis (Fig. 284).
The fifth family, Muricidæ, contains Fusus, Pyrula, Triton, and Murex.
The Murex, or Rock Shells, include a large number of species, all remarkable for their bright colours and somewhat fantastical and varied forms. They are found in all seas, but become larger and more branching in the seas of warm regions. The shell is oval, or rather oblong, the spire more or less elevated, its surface generally covered with rows of spines, or tubercular ramifications. The opening, which is oval, is prolonged in a straight canal, often of very considerable length, as in Fig. 286 (Murex haustellum); the external edge is often smooth or rippled, the columellar edge sometimes callous.
Fig. 283. Harpa imperialis (Lamarck). Fig. 284. Harpa articularis (Lamarck).
Fig. 285. Murex tenuispina (Lamarck).