34 



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 not encroach. Tabulae 

 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 D. gracile was founded upon a specimen of Lithostro- 

 tion irreaulare, 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 Kidgeway. 



Genus ERIDOPHYLLTJM (Edwards and Haime). 



" Corallum composite, and increasing by lateral gemmation. Corallites tall, cylindroid, 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. Tabulae 

 wall 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, 

 Tbut not extending into the inner or central area." (Ediv. & H. Brit. Fossil Corals. Intro- 

 duction p. Ixxi.) 



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 Diphyphyllum ; and there are also examples of Eridophyllum in which the con- 

 necting processes are few and far between, and are by no means a conspicuous feature. It 

 may be questioned, therefore, if the distinction between Eridophyllum and Diphyphyllum is 

 one that can be maintained. 



Three species of Eridophyllum have been recorded by Mr. Billings from the Corniferous 

 Limestone of Western Ontario, viz. : E. Terneuilanum (Edwards and Haime), E. Simccense 

 (Billings), and E. stridum (Edwards and Haime) ; but only the first two of these have come 

 under my notice. 



29. ERIDOPHYLLUM SIMCOENSE (Billings). 



(Plate VI. Fig. 5.) 



Eridophyllum Simcoense. (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 E. rugosum. The corallites of the latter, however, appear to be decidedly 

 more slender in tbeir dimensions, and they are stated to possess only twenty septa, though. 



