24 BRITISH FOSSIL SPONGES. 



in Tertiary strata. States that Haeckel is wrong in denying the existence of 

 calcisponges in the fossil state. Regards Astrceospongium as a calcisponge. 



129. 1875 Weight, Joseph. A List of the Cretaceous Microzoa of the North of 



Ireland (Belfast Nat. Hist. Field Club Report for year 1873-4, n. s., 



vol. i, pp. 72— 80, Pis. II, III). 

 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. 



130. 1875 Pillet, M. L., et Feomentel, M. E. Description Geologique et Paleon- 



tologique de la Colline de Lemenc sur Chambery. 

 Several species, mostly calcisponges, are described and figured, but no 

 reference is made to their minute structures. 



131. 1875 Billings, 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. 



132. 1876 Zittel, 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 

 fossilization, that the original silica of their skeletons has been replaced by 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. 



133. 1876 Zittell, K. A. Untersuchung fossiler Hexactinelliden (Neues Jahrbuch 



fur Min.,-p. 286). 

 Announces in anticipation of his monograph on Coeloptychium 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. 



