It is a question how far the colour evolved under the solar rays remains indelible. It is known that the contrary is the case with the colouring matter of the cochineal insect, which changes very quickly when exposed to the sun. It is probably the remarkable resistance it opposes to the rays of the sun which recommended it to the ancients. The patricians of Rome, and the rich citizens of Greece and Asia Minor, loved to watch the magical reflections of the sun on the glorious colour which ornamented their mantles.
But to return to our humble shells. Purpura lapillus (Fig. 277) is a thick shell, oval acute, with conical spiral, generally of a faded or yellowish white, zoned with brown, and more or less spotted.
Fig. 277. Purpura lapillus. Fig. 278. Purpura patula.
Purpura patula (Fig. 278) is very common in the Philippines, and is one of the handsomest species; its geographical distribution has been a subject of much controversy.
Purpura consul (Fig. 279) is one of the large shells, and of a fine salmon colour, with brown bands and a corona of spines.
The Buccinums resemble the Purpura in many respects. Their shell is oval or conical, much notched in front. They inhabit every sea, especially those of Europe. The animal has a small flat head, furnished with lateral tentacles or horns, bearing the eyes upon an external swelling, situated near their central length. We need only refer to Fig. 280, Buccinum senticosum, and Buccinum undatum (Fig. 281), for their general form, the well-known whelk of our markets.
Fig. 279. Purpura consul. Fig. 280. Buccinum senticosum. (Linnæus)
Fig. 281. Buccinum undatum (Linnæus).