We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 01 May 2009
In “The Palæozoic Fossils of Canada,” vol. i. p. 3, the late Mr. Billings stated that by treating a silicified specimen of Archæocyathus Minganensis with acid, he ascertained that it contained numerous siliceous spicula—slender, fusiform, slightly curved, acute at both extremities—and that these fossils must therefore be classified among the extinct tribes of sponges. Referring again to this species in the latter part of the same volume (pp. 354–357), this author states that he had found the same spicula present in great numbers in another large species, Trichospongia sericea, and that it therefore remained an open question whether they actually form part of the structure of Archæocyathus, or belonged to Trichospongia.
page 227 note 1 American Journ. of Science, n.s. vol. 45 (1868), p. 62Google Scholar; vol. 46, p. 144.
page 227 note 2 Life's Dawn on Earth, p. 154.Google Scholar
page 227 note 3 Lethæa Palsæozoica, p. 301.Google Scholar
page 227 note 4 Versteinerungen der Insel Sardinien (1886), p. 28.Google Scholar
page 227 note 5 Cambrian Faunas of North America, Bull. No. 30, U. S. Geol. Surv. (1886), p. 72.Google Scholar
page 227 note 6 Zeitsch. d. deutsch. Geol. Gesellsch. 1886, p. 899.Google Scholar
page 227 note 7 Thus we find one of the latest writers on it, MrWalcott, C.D., stating that the presence of spiculæ; in this species associates it with the Spongiæ, close to the family Euretidse of Zittel, and he considers that the spicula; “ in several of the species have been lost in the crystallization of the calcite now forming the skeleton,” I.e. p. 80.Google Scholar
page 228 note 1 American Journ. Sci. vol. xlv. p. 62.Google Scholar
