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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 Kanigi, Mant. Another genus, Mantellia, is proposed to 
include Aleyonium 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. 
1822 Manrett, 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 Alcyonites, others to Spongus 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 Choanitesis 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. 
. 1829 Ross, 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. Nach Ventriculite is regarded as a single gelatinous polype. 
. 1816-30 Dictionnaire des Sciences Naturelles. 
The classification of Lamouroux is adopted generally for fossil Sponges. 
The genus Receptaculites is described as probably belonging to the Polypiers, 
and the doubtful genus Verticillites is also placed in the same group. 
3. 1831 Benert, EK, A Catalogue of the Organic Remains of the County of 
Wilts; Pls. 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 Polypothecia. Specimens of 
Camerospongia are placed under Choanites, Mant. 
. 1826-33 Gotpruss, A. Petrefacta Germania, 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 
hving keratose Sponges. The genus Siphonia, Park., is more strictly defined, 
and the new genera Cnemidium, Myrmecium, Coscinopora, and Caloptychium 
are instituted, principally on their external characters. The spicular struc- 
ture is only referred to.as reticulate or lattice-shaped fibres or threads, which 
