The American Naturalist (Volume 13) (Paperback)

Book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1879. Excerpt: ... ON THE DESTRUCTIVE NATURE OF THE BORING SPONGE, WITH OBSERVATIONS ON ITS GEM MULES OR EGGS. BY JOHN A. RYDER. IN 1871 a vessel laden with marble was sunk in Long Island sound, and according to Prof. Verrill, the boring sponge has penetrated the exposed parts of the blocks for a depth of two to three inches from the surface. The canals or tunnels in a specimen of this marble which I have examined, vary from one-fourth to an hundredth of an inch and less in diameter; the canals are coated within with a thin film of dried sarcode of a brown color, which was orange-colored in life. Though the sarcode is dried, the needle-shaped spicules are plainly visible under a one-fifth inch lens, and display the form usually seen in the same species found on the coasts of Europe. The spicules, according to my measurements are 5l3 of an inch long, agreeing exactly with the length given by Mr. H. J. Carter as observed in British specimens, and about Ttj&tjo' of an mcn m diameter, and are, as is well known, siliceous. The specimen which I have seen, shows, in what appears to have been the inner portion of the block, a series of large branching canals which connect freely with each other in the most irregular way imaginable; moreover, the form of the canals in transverse section is exceedingly variable, being oval or irregular as often as it is circular. These last facts, together with that of the great variability in the calibre of the canals, leaves no doubt in my mind that it is the animal of the sponge which does the boring, and not marine worms which have politely abandoned their bur rows for the accommodation of this toiler of the sea. It is well known that this species and its allies are found filling systems of canals in the shells of many species of mollusks, both dead and alive, as well as in...