216 Mr. R. Etheridge and Dr. H. A. Nicholson 
ture of the greater part of the skeleton, and the vermicular 
granulation and ridging of the surface, give Paleacis a striking 
resemblance to some forms of the Stromatoporoids ; but none 
of the latter has as yet been shown to possess a minutely 
tubulated skeleton, and the cups of the former are likewise a 
unique feature in the genus. On the other hand, the micro- 
scopic tubulation of the skeleton reminds one to some extent 
of that of some of the Foraminifera. 
If we were to take Meek and Worthen’s view, founded 
upon that of Prof. Verrill, that Paleacis is a sponge, we 
should have to refer the genus to the Calcispongie, since the 
original constitution of the skeleton is undoubtedly calcareous. 
Its general structure, however, does not resemble that of any 
known calcareous sponge, so far as we are aware; and the 
tubulation of the skeleton also removes it from the Spongida. 
In fact, if we regard Paleacis as referrable to the Calci- 
spongix, it must, like the Stromatoporoids, be placed in a 
special division, since its skeleton is unquestionably reticulate 
and vermiculate, and no traces of sptcules can be detected in 
it. Indeed, were it not for the minute tubulation of the ske- 
leton and the presence of the cups, it would be difficult to lay 
down any decisive characters by which Faleacts could be 
separated from the Stromatoporoidea. 
Our friend Mr. H. B. Brady, F.R.S., has been kind enough 
to examine a few specimens and sections of this interesting 
organism ; and in his opinion there is nothing of a Foramini- 
feral character to be deduced from them; but, on the contrary, 
he appears to regard Paleacis as more probably allied to the 
Sponges. For our own part, whatever may be the ultimate 
result of a further investigation of this genus, we can simply 
state that we do not believe in its coral-affinities, and that 
there are many facts which tend to bear out the later view 
entertained by Meek and Worthen, suggested to them by Prof. 
A. E. Verrill, that Paleacis (= Sphenopoteriwm) is ‘a sponge. 
The opinion of Mr. H. B. Brady is so decided that ‘we’ are 
forced to abandon any thought of Foraminiferal affinities; 
and we can, for our own part, only say that, if not a sponge, 
we do not know where it can be placed. So many eminent 
authorities have regarded Paleacis as a coral, that we desire to 
treat their opinions with all due respect ; but the total absence 
of any trace of a columella, or septa (for the so-called “ septal 
strie ’’ can in no way be regarded as such), and the woceattag 
micro-structure compel us to dissent from this view of the 
case. We conceive that our opinion is borne out by the evi- 
dent discrepancies which exist in the eal ie and remarks 
of previous writers on the subject, and also in the want of 
