from forty to forty-four in number, alternately large and small, the small ones being very 
minute. A well-marked central tabulate area, upon which the septa do notencroach. Tabulz 
bent downwards on approaching the margin. 
I can not distinguish our forms from the species described by McCoy from the Carbo- 
niferous Limestone of Northumberland, under the name of D. gracile (Pal. Foss. p. 88). 
Milne Edwards and Haime suggest that . gracile was founded upon a specimen of Lithostro- 
tion wrrequlare, in which the columella had been accidentally destroyed in the process of fossili- 
zation (Brit. Fossil Corals, p. 199). This explanation would certainly not apply to our exam- 
ples, which are exceedingly well preserved, and exhibit no trace of a columella. The only 
distinction that I can find between the Corniferous specimens and D. gracile is that the for- 
mer are generally rather over two lines in diameter, but it does not appear that much value 
should be attached to this. . 
Locality and Formation.—Not uncommon in the Corniferous Limestone of Ridgeway. 
Genus KripoPHYLLUM (Edwards and Haime). 
“ Corallum composite, and increasing by lateral gemmation. Corallites tall, eylindroid, and 
provided with a thick epitheca, which gives rise to a vertical series of short and thick sub- 
radiciform productions that extend to the next individual and unite them together. Tabule 
well developed, and occupying the central area circumscribed by the inner wall. Septal 
apparatus occupying the annular area situated between the outer and inner mural investment, 
but not extending into the inner or central area.” (Hdw. & H. Brit. Fossil Corals. Intre- 
duction p. \xxi.) 
The only difference between Diphyphyllum and Eridophyllum is that the corallites of the 
latter are united at greater or less intervals by horizontal connecting processes. We have 
seen, however, that similar processes, though not so well developed, are sometimes present 
in species of Diphyphyllwm ; and there are also examples of Zridophyllum in which the eqn- 
necting processes are few and far between, and are by no means a conspicuous feature. It 
may be questioned, therefore, if the distinction between Lvridophyllum and Diphyphyllum is 
one that can be maintained. 
Three species of Hridophyllum have been recorded by Mr. Billings from the Corniferous 
Limestone of Western Ontario, viz.: HL. Verneuilanwn (Kdwards and Haime), E. Simccense 
(Billings), and 2. strictum (Kdwards and Haime) ; but only the first two of these have come 
under my notice. 
29. ERIDOPHYLLUM SIMCOENSE (Billings), 
(Plate VI. Fig. 5.) 
Evridophyllum Simecoense.—(Billings), Canadian Journal, New Series, Vol. IV. p. 131, 
Fig. 27. 
Corallum forming colonies of cylindrical, straight, flexuous, or crooked corallites, from two 
to three lines in diameter, distant from one another from one to three lines, and united by 
short horizontal connecting processes at intervals varying from two to six lines. The con- 
necting processes are thick where they spring from the wall of the corallite, thin in the 
middle, and again thick where they join the contiguous corallite ; and they are often, though 
by no means universally, all turned the same way in the same colony. The surface usually 
exhibits encircling folds of growth, along with vertical ridges corresponding with the septa. 
There is a well developed central tabulate area, into which the septa penetrate slightly or not 
at all. The septa are between forty and fifty in number, alternately large and small. 
Typical examples have the corallites straight, with the connecting processes placed at 
tolerably uniform distances, but many examples occur in which the corallites are very crooked 
and the intervals between the connecting processes extremely variable. Increase by parietal 
gemmation, the young individual bending upwards and becoming parallel with the older coral- 
lites, is a phenomenon which can commonly be observed. 
It is possible, as hinted by Mr. Billings himself, that Eridophyllum Simcoense may turn 
out to be identical with the Upper Silurian species described by Milne Edwards and Haime 
under the name of HZ. rugoswm. ‘The corallites of the latter, however, appear to be decidedly 
more slender in their dimensions, and they are stated to possess only twenty septa, though 
