GENERA OE EA VOSITID.E. 97 



the visceral chambers of contiguous tubes, as seen in long sec- 

 tions (fig. 17, d) ; and the presence of a few remote and large- 

 sized pores may be regarded as thus sufficiently established. 

 Taking all its known characters into consideration, I am dis- 

 posed to regard the present species as congeneric with P. 

 Fischeri, Bill., though with affinities to Coenites. 



There cannot be any question as to the identity of P. 

 froitdosa, Nich., with the form more recently described by Dr 

 Rominger from the Devonian rocks of North America under 

 the name of Cladopora Canadensis {loc. ciL) I have also a 

 number of specimens from the Devonian limestones of the 

 Eifel, which appear to be undistinguishable from P. frojidosa ; 

 but as my collections from this region are as yet imperfectly 

 examined, I shall leave this point open in the meanwhile. 



Formation and Locality. — Common in the Hamilton forma- 

 tion (Devonian) at Arkona, Ontario. 



Germs Striatopora, Hall, 1852. 

 (Pal. N. York, vol. ii. p. 156.) 



Gen. Char. — Corallum dendroid, of simply-dividing cylin- 

 drical stems. Corallites essentially polygonal, diverging from 

 an imaginary central axis, their walls greatly thickened by a 

 secondary deposit of sclerenchyma, which increases in amount 

 as their mouths are approached. Calices in the form of cir- 

 cular apertures surrounded by a cup-shaped thickened margin, 

 the floor of which is striated by rudimentary septal ridges. 

 Septal spines in vertical rows occasionally present. Tabulae 

 few, remote, complete. Mural pores comparatively numerous, 

 circular, irregularly distributed. 



Obs. — The first species of this genus which was described or 

 figured is the Striatopora lowensis of Dale Owen {^S. rugosa^ 

 Hall), of which its author gave a brief description under the 

 name of CyatJwpora lowensis (Rep. Geol. Expl. Iowa, Wis- 

 consin, and Illinois, p. 69, 1844). It is not necessary here to 



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