191. 
193. 
194. 
BIBLIOGRAPHY. 35 
1881 Watcorr, C.D. On the Nature of Cyathophycus (Amer. Journ. Science, 
vol. 22, p. 394). 
Its structure is stated to consist of narrow bands forming a horizontal 
and a perpendicular series, which cross each other at right angles. The bands 
are composed of threadlike spicula, now of pyrites. 'T'wo species are described. 
No reference is made to the form of the individual spicules beyond that they 
are threadlike. 
. 1881 Sremmany, G. Ueber ProtetraclisLinki, n. f. eine Lithistide des Malms 
(Neues Jahrbuch, Bd. i, pp. 154—163, Pl. IX). 
Describes a lithistid in which there is considerable variety in the form of 
the skeletal spicules. It is regarded as a genuine Tetracladine. The author 
also refers the Silurian genus Auwlocopium to the same family. 
1882 Hinps, G. J. Notes on Fossil Calcispongiz, with descriptions of new 
species (Ann. and Mag. Nat. Hist., vol. x, pp. 185—205, Pls. X— 
XII). 
Records the discovery in fossil Pharetrones, from the Upper Greensand, of 
three- and four-rayed spicules, which can be detached from the matrix, and are 
clearly identical in form with those of recent calcisponges. Some of them 
also occupy a similar relative position on the dermal surface of the Sponge. 
A specialised three-rayed spicule, in the shape of a tuning-fork, is present in 
the fossil genus Sestrostomella ; it closely resembles a spicule in an existing 
Australian calcisponge. These facts clearly establish that the Pharetrones 
are, as Zittel claimed them to be, true calcisponges. 
1882 Sretnmann, G. Pharetronen-Studien (Neues Jahrbuch, Bd. u, pp. 139— 
191, Pls. VI—IX. 
This paper, which appeared almost simultaneously with that by Hinde 
mentioned above, contains the results of the author’s five years study of the 
group. The Pharetrones are regarded as having been originally calcareous, 
their spicular elements are stated not to resemble those of recent calcisponges, 
since, amongst other reasons, no axial canals can be detected in them, and the 
recent spicules are stated to be so delicate as readily to melt in distilled water 
inafew seconds. Their structures are finally compared to those of Aleyonaria. 
Subsequent investigations have shown that the author’s theories respecting 
the group are altogether erroneous. 
. 1882 Zirver, K. A. Notizen itber fossile Spongien (Newes Jahrb., ui Bd., 
p- 203). 
Confirms Hinde’s observations on the spicular structure of Corynella and 
other Pharetrones, and regards their character as calcisponges to be fully 
