PERMO-CARBONIFEROUS FENESTELLIDZ. 181 
NOTES on sOME PERMO-CARBONIFEROUS FENKS- 
TELLIDAL WITH DESCRIPTIONS OF NEW SPECIKHS. 
By CHARLES FRANCIS LASERON. 
With Plates I- XVI. 
[Read before the Royal Society of N. S. Wales, June 5, 1918. ] 
Introduction. 
Fossil polyzoa are exceedingly abundant in many horizons 
in the Australian Permo-Carboniferous formation,. so 
abundant in places that their remains constitute the bulk 
of considerable rock masses. But as yet, perhaps less has 
been done to identify and study the numerous species found, 
than in any other group of Australian fossils. The reasons 
for this are fairly obvious. 
In the first place, the specimens mostly consist of casts 
or impressions in sandstone or shale. And as the structures 
on which identification depends are for the most part very 
minute, often no bigger than the grain size of the rocks in 
which they are preserved, these structures are generally 
quite lost, and the state of preservation is seldom eine 
for purposes of classification. 
Secondly,even when the state of preservation is sufficient, 
means have generally been wanting to enable adequate and 
correct illustrations to be made. Much of the pioneer 
work was done before the days of photography, and even 
in these days the possibilities of the camera do not seem to 
be adequately realised. Drawings of minute structures are 
always more or less diagrammatic, and even when correct, 
generally fail to give that ‘‘impression of a thing,”’ or as it 
is called its facies, the suggestion that is not expressed by 
point or line, but which nevertheless aids in after recog- 
nition. This is of the good drawing, but most of the 
