282 Mr. H. J. Carter on known Fossil Sponges. 
based upon a sexradiate type, coring vitreous fibre or held 
together by spongin only. 
Order VIII. Calcarea. 
Possessing calcareous spicules only. 
Now with reference to the first order, which I divided 
into Halisarcida (possessing no spicules) and Gumminida 
(possessing spicules), it could hardly be expected that the 
first division would be perpetuated in a fossilized state, or if 
so not recognizably, seeing that in the fresh state they are of 
gelatinous softness and their sponge nature can only be deter- 
mined by the microscope before they pass into decomposition 
(which 1s very rapid), or when kept under the influence of a 
preservative fluid. 
But this does not apply to the second division, where, to 
the ‘gelatinous softness,” perhaps a little inspissated, is 
added an abundance of spicules which more or less resemble 
those of other sponges, especially some of the Ho.o- 
RHAPHIDOTA in my sixth order. Thus we find Chondrilla 
phyllodes, Sdt., possessing a spiculation that hardly differs 
from that of Sptrastrella cunctatrix, Sit., which is a member 
of my family Suberitida (see also my assimilation of Sube- 
rites domuncula, Sdt., to Chondrosia reniformis in my order 
Carnosa, ‘Annals,’ 1881, vol. vill. p. 255). One could hardly 
expect under fossilization either one or the other species to 
present more than a heap of spicules of the same kind, with 
perhaps a trace of the canal-structure. But who has found 
“either one or the other,” or how could they be distin- 
guished ? | 
When we consider that the spiculiferous CARNOSA may in 
a fossilized state be hardly more than an almost shapeless 
mass of the same form of spicules, it reminds me of my 
Holasterella conferta from the Carboniferous Limestone near 
Glasgow (‘ Annals,’ 1879, vol. iii. p. 141, pl. xxi. figs. 1-8), 
in which the spicules appear to me to come nearest to those 
of Schmidt’s Adriatic species Cortictum candelabrum (Spong. 
Adriat. Meeres, p. 42, Taf. i. fig. 25); but some of the 
Suberitida might, if fossilized, present a heap of similarly 
shaped spicules to those of Cortictum abysst (‘ Annals,’ 
1873, vol. xii. p. 18, pl. 1. figs. 1-9 and 15); and Cor- 
ticium Kittont (ib. 1874, vol. xiv. p. 24, pl. xv. figs. 48 a, 
b, c) may be equally contounded with the tetrahedral form of 
a Lithistid, to which perhaps may be added Schulze’s Pla- 
