4 BRITISH FOSSIL SPONGES. 



8. 1775 Knorr, G. W., et Walch, J. E. M. Recueil de Monumens des Cata- 



strophes que la Globe de la Terre a esseuiees, contenant des petrifica- 

 tions dessinees, gravees et enluminees d'apres les originaux. 

 Many fossil Sponges are figured ; some, apparently calcisponges, are 

 regarded as Alcyonia, and their vents or oscules are stated to be the habita- 

 tions of polypes. Siliceous hexactinellid and lithistid Sponges, from the 

 Jurassic strata of Randen in Switzerland, are partly termed Fungites, and 

 placed in the same group with genuine Corals, and partly placed under Escha- 

 rites and Reteporites. 



9. 1783 Guettard, J. E. Sur plusiers corps marins fossiles de la classe des Coraux 



(Mem. de V Acad. Boy. des Sciences, vol. iv, Pis. 1 — 29.) 

 There are numerous figures of lithistid Sponges ; some are styled Cari- 

 co'ides and others Carico-Madreporites and Fungo'ides. 



10. 1774-84 Schroeter, J. S. Vollstandige Einleitung in d. Kenntniss u. Ge- 



schichte d. Steine u. Versteinerungen. 

 Mentions a lithistid Sponge under the name of Alcyoniumjicus, and regards 

 it and other Alcyonia as Corals. 



11. 1808 Parkinson, J. J. Organic Remains of a Former World. 



In the second volume, the nature of fossil Sponges is discussed in detail, 

 and the author records the results of a series of painstaking observations and 

 experiments of grinding them down and treating the surfaces with acid. They 

 are placed under Alcyonium or Spongia, and fully believed to have been pro- 

 duced by animals, though the author could form no idea of their nature. The 

 author discovered cruciform spicules in the dermal layer of a hexactinellid 

 Sponge, and noticed the quadrate arrangement of the mesh in the Jurassic genus 

 Pachyteichisma. Reference is also made to the Ventriculites in flint. Yery 

 good figures are given of numerous species of Sponges from Jurassic, Greensand, 

 and Chalk strata ; the author, however, does not assign to them distinctive 

 names, but places them all under the common term Alcyonites. 



12. 1814 Webster, T. On some new varieties of fossil Alcyonia (Transact. Geol. 



Soc, 1 S., vol. ii, p. 377, Pis. 27-30). 

 Describes and figures the lithistid Sponge now known as Jerea Websteri, 

 under the name of Tulip alcyonium. Some specimens are erroneously stated 

 to possess stems four to five feet in length. 



13. 1815 Mantell, G. A. Description of a fossil Alcyonium from the Chalk Strata 



of Lewes {Transact. Linn. Soc, vol. xi, p. 401, Pis. 27 — 30). 

 Examples of the Sponge, described later by the same author as Ventriculites 

 radiatus, are referred to under the name of Alcyonium chonoides. These forms 



