PERMO-CARBONIFEROUS FENESTELLIDZ. 187 
boniferous period with practically complete continuity; and 
they contain, especially in the lower beds, amongst other 
things, magnificent and well preserved series of Polyzoa, 
with numerous species of Fenestella and Polypora. 
Now if we apply our Australian observations to these, 
we are at once astray. For instance, amongst the numer- 
ous species of Polypora in the Upper Helderberg group, 
Hall! mentions only one, P. flabelliformis, as being fan- 
shaped, while all the others are infundibuliform, but the 
other characters of these species are certainly not those 
of Protoretepora as we know it, except that the figures of 
several show them to have thin cell walls. Sut in no cases 
are the cells shown-upon the cross-bars. In many of the 
American Polypore also, the branches are bent and the 
cross-bars ill-defined as in Protoretepora. 
So that while Australian species are on the whole well 
defined, and fall readily into two generic types, in America 
particularly, are many intermediate forms, containing some- 
times one and sometimes another of these characters, 
which here seem generically essential. 
However, after considering all the evidence, it would 
seem advisable for the present, to retain Protoretepora.as 
‘a genus, at any rate until such time as the discovery in 
Australia of further connecting links; when it may become 
necessary to discard Protoretepora in favour of McCoy’s 
genus, Polypora, or at any rate, reduce it to sub-generic 
rank, 
PROTORETEPORA MONTUOSA sp. nov. (Plates I, II, IIT, fig. 2) 
Description :—Colony infundibuliform, celluliferous upon 
the inner surface. No complete colony is known, but the 
largest specimen shows that it is capable of attaining a 
size of several inches. Branches comparatively coarse, 
J. Hall, (9). 
