apparatus consists of two unequal plumes, the leaflets of which are arranged like the teeth of a comb. An operculum is for the most part present, horny in texture, marked with lines which show the layers of progressive growth, but varying much in form, according to the different genera.
Some of the more prominent, or more interesting of the genera composing this important group, I shall slightly notice; and first of all, that fine series of shells which gives name to the family, the genus Murex. Many of the species are remarkable for their brilliancy of colouring, and for the beauty and singularity of the forms which they assume. The siphonal canal is sometimes greatly lengthened, as in the species called the Woodcock's-head (M. haustellum), and is occasionally beset, as well as other parts of the shell, with long shelly spines, as the Thorny Woodcock (M. tennispina): often the progressive stages of growth are marked by beautiful shelly foliations, as in the magnificently-hued Royal Murex (M. regius) of South America.
It was from various species of this family, but preeminently from those of the genus Murex, that the ancients obtained the purple dye which made Tyre the "crowning city." This rich hue was of great costliness; its beauty has been celebrated by poets and historians, and the very finest kinds were reserved for the hangings of temples, and the robes of kings and priests. In the reign of Augustus, double-dyed purple wool was sold for about 36l. sterling per lb. But as wealth would not hesitate at any price to obtain that which was fashionable, laws were enacted, rendering it penal for any one but the emperor to wear cloth of this sort.
