20 Spong. 
SPONGIIDA. 
Stejnmann, (20) p. 187, describes the total solution even of quite large 
pieces of a recent Calcisponge in a small quantity of distilled water, as 
showing the inapplicability of this medium to the purpose of preserving 
parts of Calcar ea. 
Fossil Sponges, Chief Works on. 
18. Hinde, G. J. Notes on Fossil Calcispongice , with descriptions of 
new species. Ann. N. H. (5) x. p. 185, pis. x.-xii. 
A study of the Pharetrones, resulting in the upholding of this group as 
a member of the Order Calcarea. 
19. Miller, S. A. Description of two new genera and eight new species 
of Fossils from the Hudson River Group, with remarks upon others. 
J. Cincinn. Soc. v. p. 34, pis. i. & ii. 
Includes Sponges, besides Echinodermata , &c. 
20. Steinmann, G. Pharetronen-Studien. JB. Mineral, ii. p. 139, 
pis. vi.-ix. 
From a consideration of their geological distribution — Devonian to later 
Chalk — the very variable external form, the minute structure of the 
fibres and their spicules, and the condition in which they are found pre- 
served, the author concludes that the group does not consist of calcareous 
Sponges, but forms an independent division of the Ccelenterata, in part 
greatly resembling the Sponges in their habitus, in part the Hydrozoa , 
but having some characters peculiar to themselves. Their dermal 
skeleton is represented only in the “ star-corals ” and Hydrozoa , and 
their skeletal structure can only be compared to that of the Alcyonaria. 
For some other arguments, and for the detailed classification and new 
forms, see below. 
21. Zittel, A. K. Notizen fiber fossile Spougien. JB. Mineral, ii. 
p. 203. 
Dunikowski, E. von. Die Spongien, Radiolarien, und Foraminiferen 
der Unterliassischen Schichten von Schatberg bei Salzburg. Denk. 
Ak. Wien. xlv. p. 163, pis. i.-vi. 
From the low horizon of the lower Lias, are described skeletal remains 
referred to 4 species of Monactinellida (the most abundant Order), 18 
Tetractinellida (including one Lithistid), and 16 Hexactinellida. The 
author states that individuals are very abundant : the spicules are fouud 
composed of crystalline silex. 
Dunikowski, l. c ., describes and figures from the lower Lias, without 
specific names, the following Monactinellida : — Opetionella ? sp., lieniera 
or Suberites sp., Scoliorraphis ? sp., Esperia ? sp., pp. 167-169, pi. i. figs ; 
Tetractinellida : — Pachyastrella P 5 spp., Stelletta P 8 spp., Geodia , or P 4 
spp , Lithistid sp., pp. 169-176, 181, pis. i.-iv. figs.; Hexactinellida : — 
Stauractinella , 10 spp., Hyalostelia , 2 spp., Tremadictyon , 3 spp., Craticu- 
laria ? sp., pp. 175-181, pis. iii. & iv. figs. 
Hinde (18) considers that the condition in which the Pharetrones 
