CORALS OF THE COENIFEKOUS LIMESTONE. 231 



uniform dimensions, and their possession of a single row of large mural 

 pores on each of the flat faces. 



I have seen fine specimens of this species from the Corniferous lime- 

 stone of Ohio, and it is one of the commonest and most characteristic 

 fossils of the same formation in Canada. It also occurs, though not so 

 abundantly, in strata of the age of the Hamilton group, in western On- 

 tario. 



Position and locality : Corniferous limestone, Kelley's Island, Ohio. 



Favosites polymorpha, Goldfuss. 



Calamopora polymorpha, Goldfuss ; Petref., pi. 27, figs. 26, 2c, 2d, 36, and 3c. (Oset. 

 exclusis.) 



Corallum more or less lobate or sub-dendroid, varying in shape and 

 size. Calices more or less polygonal, sometimes becoming round by the 

 thickening of the walls of the corallites, of unequal sizes, a few small 

 ones being intercalated amongst the larger. The diameter of the larger 

 calices is generally from half a line to two-thirds of a line. 



It seems questionable whether the strictly dendroid forms of Favosites, 

 usually described under the names of F. reticulata, DeBlain., and F. dubia, 

 DeBlain., can be separated from F. polymorpha proper, but I have omit- 

 ted any allusion to their characters in the above definition. It seems 

 also doubtful if F. cervicornis, DeBlain., and F. cristata, Edw. and H., can 

 be kept apart from this form. 



Position and locality : Corniferous limestone, Antwerp, Ohio. 



Favosites PLEUEOBiCTyoiDES, Nicholson. 



Plate 23, figs. 3, 36. 



Corallum circular, depressed, apparently discoid, the under surface 

 being flat or slightly concave. The lo'wermost corallites are parallel with 

 the lower surface, and radiate from the central point like the spokes of 

 the wheel. The corallites are prismatio or sub-cylindrical in shape, 

 about one line in width near the base, but often rapidly widening as they 

 approach the circumference of the colony, their walls pierced with two 

 very distinct rows of alternating mural pores, resembling those of F. Goth- 

 landica. Epitheca thin, continuous, but deeply grooved along the lines 

 of junction of the difierent corallites, concentrically striated, and also 

 exhibiting faint longitudinal striae. Upper surface and calices unknown. 



