8 BRITISH FOSSIL SPONGES. 



32. 1839 Bronn, H. G. Lethasa geognostica. 



In this work the following genera of fossil Sponges from Oolitic and 

 Cretaceous strata are stated to possess an internal fibrous reticulated structure, 

 Scyphia, Tragos, Mammillopora, Cnemidium, Myrmecium, and Hlppalimus. 

 Some of these genera are supposed to include horny Sponges, both recent and 

 fossil. 

 83. 1839 Hagenow, F. v. Monographie der rugenschen Kreideversteinerungen 

 (Neues Jahrb., p. 260). 

 The Sponges are placed with Corals and Polyzoa as Polyparien. Species of 

 Achilleum, Manon, Scyphia, and Siphonia are named, and references given. 



34. 1839 Murchison, It. I. Silurian System. 



Names and gives a figure of Ischadites Koenigii (p. 697, PI. xxvi, fig. 11). 

 Its affinities are considered very doubtful. 



85. 1840 Roemer, F. A. Die Versteinerungen des norddeutschen Kreidegebirges. 

 Numerous species of Sponges, many of them new, are described. They 

 are for the most part placed in the meaningless genera, Spongia, Achilleum, 

 Manon, Tragos, Cnemidium, and Scyphia. The new genus Pleurostoma is 

 constituted. The descriptions are very brief and indefinite, and regard chiefly 

 external characters. The minute spicular structure of many hexactinellid 

 Sponges is described as lattice-shaped fibre and distinctly figured, but these 

 Sponges are included in the same genus with lithistid and calcisponges. 



36. 1841 Munster, Graf zu. Beitriige zur Petrefacten-Kunde. 



Numerous species of Calcisponges from the St.-Cassian beds are described 

 and figured. They are regarded as polyps and placed in the genera Achilleum, 

 Scyphia, &c. 



37. 1842-44 Koninck, L. de. Description des Animaux fossiles dans le terrain 



carbonifere de Belgique. 

 Describes as a new genus of Corals, Mortiera ; a biconcave siliceous fossil, 

 composed of thin lamella?. It is now regarded as a Sponge (P. 12, 

 PL B, fig. 3). 



38. 1842 Bowerbane, J. S. On the Spongeous Origin of Moss-agates and other 



Siliceous Bodies {Ann. and Mag. Nat. R., vol. x, pp. 9, 84, Pis. 

 i — iii). 

 The fibrous appearances in sections of moss-agates are stated to be due to 

 the presence of keratose Sponges, and the chert of the Greensand strata and 

 the flints from the Chalk are believed to have been produced by the continued 

 attraction and solidification by keratose Sponges of the silex in solution in the 

 ocean. 



