150. 
132. 
BRITISH FOSSIL SPONGES. 
in Tertiary strata. States that Haeckel is wrong in denying the existence of 
calcisponges in the fossil state. Regards Astrawospongium as a calcisponge. 
. 1875 Wricut, JoserH. A List of the Cretaceous Microzoa of the North of 
Treland (Belfast Nat. Hist. Field Club Report for year 1873-4, n. s., 
vol. i, pp. 72—80, Pls. II, ITI). 
Amongst these are numerous detached siliceous spicules, obtained from 
the interior of flints from the Upper Chalk, which were compared by Dr. 
Bowerbank to the spicules of Tethea, Geodia, Dactylocalyx, and other siliceo- 
fibrous Sponges. 
1875 Pitter, M. L., nt Fromenter, M. H. Description Géologique et Paléon- 
tologique de la Colline de Lémene sur Chambéry. 
Several species, mostly calcisponges, are described and figured, but no 
reference is made to their minute structures. 
. 1875 Bruurnes, E. On some new or little-known Fossils from the Silurian 
and Devonian Rocks of Ontario (Canadian Nat. and Geologist, n. s., 
vol. vii, p. 230, figs. 1, 2). 
The genus Aulocopina is defined, and its form and canal-structure is stated 
to resemble Aulocopium, Oswald. The spicular characters are unknown. 
1876 Zirrer, K. A. Untersuchungen iiber fossile Spongien. Protokoll der 
Sitzung der deutschen geologischen Gesellschaft zu Jena, vom 14 
August, 1876 (Zeitsch. d. deutsch. geol. Gesellschaft, Bd. 28, 1876, 
p. 629). 
Prof. Zittel states that the majority of the so-called Petrosponges have 
undergone great alteration in their mineral structures in the course of 
fossilzation, that the original silica of their skeletons has been replaced by 
calcite, and that owing to the delicacy of their siliceous fibres and the pre- 
sence of axial canals, they become readily susceptible to the solvent influences 
of alkaline waters. A great part of the Petrosponges is stated to belong to 
the same group as the existing hexactinellids and lithistids, whilst in another 
division the fibres consisted originally of calcite. 
. 1876 Zirrevt, K. A. Untersuchung fossiler Hexactinelliden (Neues Jahrbuch 
fiir Min., p. 286). 
Announces in anticipation of his monograph on Celoptychium the resem- 
blance between the structure of this genus and Ventriculites, and states that 
the skeleton consists of amalgamated six-rayed spicules with a hollow 
octahedral node in the centre of each. 
