BIBLIOGRAPHY. 23 



123. 1874 Rutot, A. Note sur la decouverte de deux Spongiaires de l'Etage 



Bruxellien des environs de Bruxelles (Ann. de la Societe Malaco- 



logique de Belgique, Tome ix, pp. 1 — 14, PI. 3). 

 Numerous siliceous accretions occur in these Tertiary beds, which are 

 largely composed of the detached spicules of siliceous tetractinellid Sponges. 

 These accretions are erroneously regarded as definite Sponges, and on them 

 two species are based, Stelletta discoidea and Dysidea tubulata. 



124. 1874 Wyville-Thomson, C. The Depths of the Sea. 



The essential similarity in the minute skeletal structures of recent hexac- 

 tinellid Sponges and of the Ventriculites of Toulmin Smith, is pointed out. An 

 erroneous comparison is made between the general structure of Coelosphcera 

 tubifex, a recent monactinellid Sponge, and Choanites, a fossil lithistid, the 

 body-canals of this latter form being mistaken for tube-like processes, present 

 in the existing Sponge. 



125. 1874 Davet, E. C. The Sponge-Gravel Beds at Coxwell near Faringdon. 



A general description is given of the deposit, and reference made to the 

 Sponges with which it is filled ; they are placed in the obsolete genera Marion, 

 Tragos, &c. 



126. 1874 Meyn, L. Silurische Schwamme und deren eigenthiimliche Verbrei- 



tung, ein Beitrag zur Kunde der Geschiebe (Zeits. d. deutsch. geol. 

 Gesell., vol. xxvi, pp. 41 — 58). 

 Treats of the state of preservation and mineral condition of the fossil 

 Sponges in the Drift deposits of the Island of Sylt. 



127. 1875 Gumbel, C. W. Beitriige zur Kenntniss der Organisation und 



systematischen Stellung von Receptaculites (Abh. der h. bayer. 



Akad. der Wiss., II 01., Bd. xii, 1 Ab., pp. 169—215, PI. A). 

 A minute detailed description of the characters of the genus is given, its 

 thick inner and outer walls are stated to consist of individual plates held in 

 position by intervening pillars, and a branching canal-system is also present. 

 The genus is included in the Foraminifera in close relationship to Dactylopora. 

 The genus Ischadites is regarded as similar generically to Receptaculites, 

 and Protospongia is also a related form. 



128. 1874-75 Baerois, Ch. Sur la Philogenie des Eponges (Ann. Soc. Geol. Nord, 



pp. 71—73). 

 Refers to the presence of lithistid spicules in Devonian Sponges, and the 

 abundant development of the hexactinellidas in the Chalk, and of the Corticatse 



