The sepia of the artist comes from a mollusk, and is the fossil or extant ink-bag of a cephalopod or squid, while the cuttle-fish bone is used for a variety of purposes. In the islands of the Pacific the young of the pearly nautilus are strung upon strings and sold for $25 and $20 as necklaces. The tritons are in fair demand, and many tons of cowries are sent to Europe yearly, while the shipment of a thick-lipped strombus in one year to Liverpool amounted to 300,000. The rich coloring of the haliotis is used for inlaying art furniture. From the pinna, silk of a peculiar quality is obtained. It is the byssus or cable of the animal. The threads are extremely fine, and equal in diameter throughout their entire length. It is first cleaned with soap and water, and dried by rubbing through the hands, and finally passed through combs of bone, iron, or wood, of different sizes, so that a pound of the material in the rough gives only about three ounces of pure thread. It is mixed with a third of real silk and spun into gloves, stockings, etc., having a beautiful yellow hue. The articles made from it are, however, not in general use. A pair of gloves from pinna silk would cost $1.50, and stockings about $3. Fine specimens of such work can be seen in the British Museum. Though not of animal origin, amber is one of the choicest vegetable productions used in the arts. It is the fossil gum of pines. Great beds of it occur at various points in Europe. On the Prussian seaboard it is mined, and often washes ashore. In 1576 a piece of amber was found that weighed thirteen pounds, and for which $5,000 was refused. In the cabinet of the Berlin Museum there is a piece weighing eighteen pounds. Ambergris, from which perfumery is made, is a secretion taken from the intestines of the whale, and a piece purchased from the King of Tydore by the East India Company is reported to have cost $18,000. Whales' teeth, the tusks of elephants, and those of the walrus and narwhal, are all used. Elephants' feet are cut off at a convenient length, richly upholstered, and used as seats; the great toe-nails, when finely polished, giving the novel article of furniture an attractive and unique appearance. It is probably not generally known that the web of certain spiders has been used. Over 150 years ago, Le Bon, of France, succeeded in weaving the web material into delicate gloves. Prof. B.G. Wilder investigated the question thoroughly, and was a firm believer that the web of the spider had a commercial value, but as yet this has not been realized. It would be difficult to find an animal that does not in some way contribute to the useful or decorative arts.--_C.F.H., in N.Y. Post_. * * * * * A catalogue, containing brief notices of many important scientific papers heretofore published in the SUPPLEMENT, may be had gratis at this office. * * * * * THE SCIENTIFIC AMERICAN SUPPLEMENT. PUBLISHED WEEKLY.