182 C. F. LASERON. 
published illustrations of the Fenestellidee are anything but 
good. This has rendered the task of identifying specimens. 
with described species very difficult; and as the types are 
in most cases unavailable, the difficulty is not lessened. 
De Koninck’s types were destroyed in the Garden Palace 
fire, Dana’s are in America and Lonsdale’s, supposed to be 
in London, are now untraceable. 
Fortunately, descriptions by Lonsdale, who has done the 
bulk of the work on Australian forms, are accurate, and 
there is less difficulty in recognising his species, than in 
the case of other authors. But, as previously remarked by 
other writers, very little dependence can be placed either 
on the description or on the figures in de Koninck’s work; 
for instance, in recording Polypora papillata McCoy, his 
description and figure are entirely at variance, and in a 
case like this, where an Australian specimen has been 
doubtfully identified with a form from a different formation 
at the antipodes, I think it is justifiable to expunge the 
record, until such time, if ever, the species is re-discovered 
or identified. 
A third difficulty is often presented, even when speci- 
mens are well preserved, in identifying the celluliferous 
with the non-celluliferous surface of the same species. 
Owing to the cells themselves becoming filled with matrix, 
this side generally adheres to the rock when a slab is split; 
and as a result, by far the majority of specimens display 
the non-celluliferous side. However, by carefully remov- 
ingafragment with a pocket-knife, it is possible in most 
cases to correlate the two sides of the one species. 
With reference to the photographs in this paper, a word 
might be said. For such groups as the Fenestellide, micro- 
sections are of little use, for most of the important char- 
acters are surface ones, and in addition, sections of shale 
or sandstone are very difficult, if not impossible to make. 
