6 BRITISH FOSSIL SPONGES. 



of tubes." Many different forms of Sponges are included in the genus, but 

 the specimen first referred to it, and therefore the type of the genus, is now 

 known as Siphonia Eoenigi, Mant. Another genus, Mantellia, is proposed to 

 include Alcyonium chonoides, Mant., but the characters given are very indefi- 

 nite, and the specimen figured as an example does not belong to the same 

 genus as Mantell's species. 



20. 1822 Mantell, G. A. The Fossils of the South Downs, &c. 



Many of the commoner fossil Sponges from the Upper Chalk are described 

 and figured. Some are referred to Alcyonitcs, others to Spongns and 

 Spongia. The genus Ventriculites is constituted ; the forms are believed to 

 have been originally of a spongeous or gelatinous substance, possessing con- 

 tractile properties. The genus Choanites is proposed, but the characters given 

 are too indefinite to be of any value, and the three species placed under it 

 belong to as many different genera. 



21. 1829 Rose, C. B. On the Anatomy of the Ventriculites of Mantell (Mag. Nat. 



Hist., vol. 2, p. 332). 

 The author agrees with Mantell that they are retractile, and they are stated 

 to consist of an inner coat, with the openings of transverse tubes, a reticulated 

 parenchyma, and an external coat, partly of a coriaceous and elastic integu- 

 ment. Each Ventriculite is regarded as a single gelatinous polype. 



22. 1816-30 Dictionnaire des Sciences Naturelles. 



The classification of Lamouroux is adopted generally for fossil Sponges. 

 The genus Beceptaculites is described as probably belonging to the Polypiers, 

 and the doubtful genus Verticillites is also placed in the same group. 



23. 1831 Benett, E. A Catalogue of the Organic Remains of the County of 



Wilts; Pis. 1—15. 

 Excellent figures are given of numerous forms of lithistid Sponges from 

 the Upper Greensand and the Upper Chalk. The Sponges are not described, 

 but they are included in the common term Polijpothecia. Specimens of 

 Camerospongia are placed under Choanites, Mant. 



•24. 1826-33 Goldeuss, A. Petrefacta Germanise, vol. i. 



Fossil Sponges are regarded as the remains of Zoophytes, the plant-animals 

 of the past. Numerous new species are described, and they are, for the most 

 part, placed under the indefinite generic terms proposed by Schweigger for 

 living keratose Sponges. The genus Siphonia, Park., is more strictly defined, 

 and the new genera Cnemidium, Myrmecium, Coscinopora, and Coeloptychium 

 are instituted, principally on their external characters. The spicular struc- 

 ture is only referred to as reticulate or lattice-shaped fibres or threads, which 



