BIBLIOGRAPHY. 31 



group. Two new genera are proposed, Opetionetta and ScoliorfiapMs. The 

 Tetractinellidas are likewise rarely found as entire Sponges, though their 

 spicules occur even in Carboniferous Rocks. A new species of Pachastrella 

 is described, and a new genus Tethyopsis. Fossil calcisponges are shown to be 

 very numerous. The views of Haeckel and Carter that Sponges of this group 

 could not be preserved as fossils are discussed and regarded as erroneous. 

 With the exception of a single form, Protosycon, fossil calcisponges belong 

 to a distinct family, characterised by a skeletal structure of anastomosing 

 fibres. These fibres are built up of minute uniaxial and three-rayed spicules, 

 comparable to those of existing calcisponges. It is shown that these 

 fossils are not, as stated by Carter and Sollas, siliceous Sponges which have 

 been replaced by calcite. In the new family, Pharetrones, several new genera 

 are introduced, as well as many genera of previous authors, including 

 Pharetrospongia, Sollas. 



168. 1878 Zittel, K. A. Handbuch der Palaeontologie, Bd. i, II Lief. 



Descriptions are given of the various groups of fossil Sponges, similar to 

 those in the " Studien." Diagnoses of all the genera are given, and illustrations 

 of the typical forms. The genus Hyalostelia is proposed to include Hyalonema 

 Smithii, Young. 



169. 1878 Sollas, W. J. Notes on the Ventriculites of the Chalk (Dixon's Geology 



of Sussex, New Edition, pp. 448—455, Pis. XL VI— LI). 

 Describes the spicular structure and other characters of the genus ; the 

 former is compared with the structure of the recent hexactinellid, Myliusia 

 Grayi. 



170. 1879 Zittel, K. A. Beitriige zur Systematik der fossilen Spongien. Dritter 



Th., Neues Jahrbuch, pp. 1—40, Pis. I, II. 

 Mostly a reprint from Abhand. der k. bayer. Akad der Wiss., II CI., 

 xiii Bd. 



171. 1879 Zittel, K. A. Studies on Fossil Sponges, III, IV, V, Monactinellidse, 



Tetractinellida3, and Calcispongise (Ann. and Mag. Nat. Hist., S. 5, vol. 

 iii, pp. 304-312, 364—379 ; also vol. iv, pp. 61—73, 120—135. 

 Translated by W. S. Dallas from the " Studien," Dritte Abth. 



172. 1879 Nicholson, H. A. Manual of Palaeontology, 2nd Edition. 



The first part of the volume was written before the works of Zittel were 

 fully published, and consequently it is mainly interesting as indicating the 

 generally received views held at the time on fossil Sponges. Astrceospongia, 

 Ampkispongia, and provisionally Stromatopora and Archceocyathus are included 

 with calcisponges. Zittel's classification is adopted for fossil siliceous 



