132 
Dime7isions—T\ih species is capable of reaching a very large size. I 
have seen some very incomplete specimens of it which were sixteen centi- 
metres long, and from ten to twelve centimetres broad. I have counted, 
rather regularly, nineteen fenestrules for each centimetre of length. 
Relations and Differences . — After having, with great care, com- 
pared the Australian specimens with a large number of specimens collected 
from the Carboniferous Limestone of Scotland, Ireland, and Belgium, I am 
convinced that the Fenestella, described by Lonsdale under the name F. 
fossula differs in no way from that which McCoy has figured under the 
name F. i^leheia. Their identity having been established, the question arises 
which of the two names should have the preference. This question does not 
appear to me difficult to answer, for, by reference to the list of synonyms 
given above, it will be seen that the works containing notices of this species 
appeared in the same year, and probably about the same time ; but it must 
be admitted that Lonsdale’s description is very incomplete, and not suffi- 
ciently detailed to help one to recognise with certainty the species to which 
it is applied ; while McCoy’s description, besides giving more characteristics, 
is accompanied by an excellent figure, making confusion with allied species 
impossible. Again, the figure of F. fossula^ Lonsdale, did not appear until 
1815, so that I think the name given by McCoy ought to have the preference, 
and it is the one I shall adopt. In 1812 I confounded this species with F. 
retiformis, Schlotheim, to which it bears so great a resemblance that, twenty 
years after, Kirkby made the same mistake. But in comparing two well- 
preserved specimens of each species, it is easy to see that the fenestrules of 
F. retiformis are oval, while they are rectangular in F. pteheia ; also that the 
number of cells between the cross-bars is usually different. It may not be 
impossible that the species so carefully described by E. B. Meek, under the 
name of F. Stmmardi, Prout, is merely a dwarf variety of F. ptebeia, McCoy. ^ 
IIorizo7i a7id Localities.-— As, I noted in 1873,^ this species is found 
exclusively in the Carboniferous System. I tliink it is correct to state that it 
is confined to the middle and upper beds of limestone belonging to this system. 
It has been pointed out by McCoy in a large number of localities in Ireland. 
It is not uncommon about Glasgow, and in certain parts of Derbyshire and 
Yorkshire. It has been found also in the Ural and at Bleiburg, in Prussia. 
Lonsdale found it at Mount 'Wellington, in Tasmania ; at Patrick’s Plains 
^ r. B. Meek, Report on the Paleontology of Eastern Nebraska, p. 153, pi. 7, fig. 3. 
^ Consult Vol. II of iny Recherches sur les Animaux Fossiles, p. 12. 
