The genus _Buccinum_ resembles that of the _Purpura_ in many respects. The common whelk belongs to the series. Thus one of the humblest of our shell‐ fish is allied to the animal from which a nearly priceless dye was once obtained. [Illustration: MUREX.] [Illustration: HARPA.] [Illustration: CLEODORA.] The genus _Harpa_ includes some beautifully marked and coloured shells, of which _H. ventricosa_ is an attractive example. These are chiefly found in the Indian Ocean. The Rock Shells (_Murex_) abound in every sea, but are finer and more branching in the warmer ones. They are remarkable for bright colours and fantastic forms. The shell is oblong with a long spire attached, its surface often covered with rows of branching spines. The genus _Triton_, of which about one hundred species are known, is ranged with the genus _Murex_, on account of points of similarity. The Marine Trumpet (_Triton variegatum_) which sometimes attains a length of sixteen inches, is a fine example. The genus _Strombus_ includes among its species the great roughly ornamental shells, often used for grottoes or rockeries. Some of the streets of Vera Cruz are said to be paved with them. Oddest and most remarkable of all the marine shells to be found in the naturalist’s collection are those of the genus _Pteroceras_. They are of fresh and brilliantly shaded colours. [Illustration: STROMBUS.] [Illustration: TRITON.]