. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. CYPRiEA.—CONUS. 57. tracted at the two extremities, has a very narrow aperture, trans- versely wrinkled on both sides; when the animal expands it- self, the mantle extends over the shell and envelopes it entirely {fig. 69), which, in the progress of time, pro- duces considerable mo- dification in the colours of the latter; for, at a certain period, it depo- sits new layers of calca- reous matter, not only around the aperture, but also upon the whole external surface of this solid envelope. 18. Also to this tribe
. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. CYPRiEA.—CONUS. 57. tracted at the two extremities, has a very narrow aperture, trans- versely wrinkled on both sides; when the animal expands it- self, the mantle extends over the shell and envelopes it entirely {fig. 69), which, in the progress of time, pro- duces considerable mo- dification in the colours of the latter; for, at a certain period, it depo- sits new layers of calca- reous matter, not only around the aperture, but also upon the whole external surface of this solid envelope. 18. Also to this tribe of mollusks belongs the genus CoNus {fig. 70), which differs from all the preceding in the conical form of the shell, which gives the genus its name; a slightly, or not at all projecting spire, forms the base of this cone, and the aperture, which is nearly straight, extends from one end of the shell to the other. 19. A great number of the shells, the principal characters of which we have briefly noted, are re- markable for the elegance of their form and the beauty of their colours; the Cones, the porcelain shells (Cyprsea), the Volutes, and the Olives especial- Fig. 70. ly, are much admired for the brilliance of their mark- conus. ings. Many other mollusks of the family of Buccinoides are also worthy of attention on account of the viscid liquid, secreted by the gland placed, as we have already seen in the snails, betwixt the heart and rectum. And in a considerable number of these animals, this humour has the property of changing colour when exposed to the action of air and light, and thus passes from greenish yellow to purple; spread upon stuffs, it imparts to them this rich shade, and appears to be the material employed by the ancients for producing their beautiful purple dyes. Pliny relates that on the shores of Tyre, and many other points along the coasts of the Mediterranean, there are found two genera of shells, called Buccinum and Purpura^ both of which furnished dye f
Size: 2286px × 1093px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
