168. 
169. 
170. 
ile 
BIBLIOGRAPHY. 31 
group. Two new genera are proposed, Opetionella and Scoliorhaphis. The 
Tetractinellide are likewise rarely fonnd as entire Sponges, though their 
spicules occur even in Carboniferous Rocks. A new species of Pachastrella 
is described, and a new genus Tethyopsis. Fossil caleisponges 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been replaced by calcite.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. 
1878 Zirran, K. A. Handbuch der Palaeontologie, Bd. i, IT 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. 
1878 Sottas, W. J. Notes on the Ventriculites of the Chalk (Divon’s Geology 
of Sussez, New Edition, pp. 448—455, Pls. XLVI—LI). 
Describes the spicular structure and other characters of the genus; the 
former is compared with the structure of the recent hexactinellid, Myliwsia 
Gray. 
1879 Zirret, K. A. Beitriige zur Systematik der fossilen Spongien. Dritter 
Th., Newes Jahrbuch, pp. 1—40, Pls. I, II. 
Mostly a reprint from Abhand. der k. bayer. Akad der Wiss., II Cl., 
xi Bd. 
1879 Zirrer, K. A. Studies on Fossil Sponges, III, IV, V, Monactinellide, 
Tetractinellide, and Calcispongiz (Ann. and Mag. Nat. Hist., 8. 5, vol. 
li, pp. 804—312, 364—379 ; also vol. iv, pp. 61—78, 120—1535. 
Translated by W. 8. Dallas from the “‘ Studien,” Dritte Abth. 
. 1879 Nicnotson, H. A. Manual of Palaeontology, 2nd Kdition. 
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. Astre@ospongia, 
Amphispongia, and provisionally Stromatopora and Archeocyathus are included 
with calcisponges. Zittel’s classification is adopted for fossil siliceous 
