THE MTJREX. 313 



Another shell belonging to the same family is the Three-horned Stromb. 



The Strombs form a large germs, containing about sixty species, and are found in almost 

 every warm sea. They do not appear to be deep-water lovers, being mostly found on the 

 reefs at low water, and seldom extending their range beyond ten fathoms. The operculum of 

 the Strombs is rather curious in its structure, the nucleus being set at one extremity, and the 

 operculum being made up of a succession of horny plates or scales overlapping each other like 

 the tiles of a house, or the successive steel layers of a carriage-spring. 



Some species of Strombs attain a considerable size, and are much used in the arts, as, for 

 example, the Giant Stromb, or Fountain Shell (Strombus gigas), one of the West Indian 

 species, which sometimes attains the weight of four or five pounds, and is exported to America 

 and Europe by thousands for the use of engravers, who cut the well-known cameos from 

 its beautifully tinted substance. Three hundred thousand of these shells were brought to 

 Liverpool alone in a single year. As the animal increases in age, it gradually fills up the 

 hollow apex and spines with solid matter, and thus materially adds to the weight of the shell 

 without improving its value to the engraver. In some parts of the world, such as Barbadoes, 

 the Giant Stromb is eaten, and sold regularly for that purpose. Pearls of a delicate pink 

 color have sometimes been found in this shell, but their occurrence is not frequent, probably 

 on account of the careless and unobservant habits of the negroes who clean the shells. Pearls 

 are also found in other species belonging to this genus. 



The teeth of the Strombs are extremely beautiful and most complicated. 



The color of the Three-horned Stromb is brown and yellow of different shades, richly 

 mottled with pale saffron. Its average length is about four inches. 



The two species, the Common Spider-shell, and the Orange-mouthed Spider-shell, 

 derive their popular names from the generally spider-like contour of their form. 



When adult, the outer lip is furnished with several horny appendages, always curved 

 and not precisely of the same shape in the same species, although the general character 

 of their form is sufficiently well marked to distinguish the species. One of these horns 

 is always close to the spine, and is rolled in such a manner as to form a posterior canal. 

 About ten species of these animals are known, and seem to be confined to the Chinese and 

 Indian seas. 



The color of the Common Spider-shell is very bright, consisting of boldly mottled chestnut, 

 like the hue of old rosewood, variegated with white, and traversed by lines of orange. The 

 interior of the shell is pale brown, with a dash of yellow. The average length is three 

 or four inches. 



The shell of the Orange -mouthed Spider-shell is remarkable for its curious projecting 

 horns, with their sharp points and bold curves. It is worthy of notice that in all the Spider- 

 shells these projections are not developed until the creature has attained adult age, the young 

 Spider-shell resembling that of the stromb. From the peculiar shape of some of the species, 

 these creatures are sometimes called Scorpion-shells. 



The color of the Orange- mouthed Spider-shell is creamy- white on the exterior, and rich 

 orange within. The curved spines are white and shining, and bear no small resemblance 

 to the poison-teeth of serpents. 



The shells that are included in the family of the Murickhe may readily be distinguished 

 by the straight beak or canal in front, and the absence of any such canal behind. The eyes of 

 these animals are not placed on long footstalks, as in the preceding family, but are set directly 

 on the tentacles, without any supporting stalk or projection. All the animals belonging to this 

 family are not only carnivorous, but rapacious, preying on other mollusks, and destroying them 

 with the terrible armature called the tooth-ribbon, and which, when examined with a micro- 

 scope, proves to be a set of adamantine teeth, sharp-edged and pointed as those of the shark, 

 and cutting their way through the hard shells of their victims as the well-known cordon saw 

 passes through thick blocks of hard wood. 



About one hundred and eighty species are known to belong to the typical genus, and there 

 is hardly a portion of the world where a Murex of some kind may not be found. 



Vol. IU.-40. 



