Читать книгу The Book of Shells. Containing the Classes Mollusca, Conchifera, Cirrhipeda, Annulata, and Crustacea онлайн
23 страница из 32
Harpa musica.
The foot of the animal has the power of dividing itself into two portions; and one, namely, the hinder portion, can be separated from its body by the animal, when it finds itself suddenly in danger, and wishes to retire into the deepest recess of its shell; on this account it is without an operculum, which would evidently be useless, as it would be lost at the same time as the foot.
The Harps, says Lamarck, are very beautiful shells, and if they were less common, would, on account of their elegant forms and colours, become valuable in a collection. Some species, however, are still considered rare.
The Harps take their name from the fancied resemblance between the regularity and direction of the ribs on the shell, and the strings of a harp. The species are not numerous, not exceeding eight in number.
The Wide-Mouthed Purpura, (Purpura patula.)
This species of Purpura is said to be that which was employed by the Romans in dyeing, but many others of the same family yield a purple colouring-matter. It is nearly three inches in length, and is found in the Atlantic Ocean and the Mediterranean.