190 CONTRIBUTIONS TO CANADIAN PAL«0NTOL0GV. 



Although this species is retained in the genus to which it was originally 

 assigned by Mr. Billings, the writer is strongly of the opinion that it 

 should form the type of a separate genus as its structure is quite dis- 

 similar in its main features to that of the Silurian corals grouped round 

 the type C. perfoliatum, Goldfuss, sp. 



CYSTIPHYLLID^. 



Genus Oystiphyllum, Lonsdale. 1839. 



(Ety. Kvo-rts, cavity, <^vXkov, leaf.) 



Cystiphyllum, Lonsdale. 1839. Mureh. Sil. Syst., pt. II., p. 691. 

 Conophyllum, Hall. 1852. Palseon. New York, vol. II., p. 114.. 



Corallum simple or aggregate. Corallites varying from conical to cylin- 

 drical ; when aggregate, increasing by lateral calicinal budding. Epitheca 

 complete. No true tabulae nor septa. Inner structure vesicular, com- 

 posed of convex plates curving upward and outward, the central ones 

 more nearly horizontal and generally larger than the others. Septa 

 represented by radial rows of denticulations, or by spinulose or rounded 

 ridges, on the upper surface of the blister-like plates. In one species 

 (C. sulcatum) a distinct fossette, with at times two obscure lateral ones, 

 is present in the calyx, as well as faint septal furrows on the surface 

 showing a pinnate arrangement. Calyx of varying depth, its concave 

 surface formed of the uppermost blister-like plates that in the case of C. 

 sulcatum combine to form a continuous laminar floor marked by superfi- 

 cial radiating rounded ridges. 



Type species. — C. Siluriense, Lonsdale. 



Range. — Silurian, Devonian. 



Oystiphyllum Niagarense, Hall. (Sp.) 

 Plate XVI., fig. 7. 



Conophyllum Niagarense, Hall. .1852. Palaeon. New York, vol. II., p. 114, pi. 32, 



figs. 4a — n. 

 Oystiphyllum Huronense, Billings. 1866. Cat. Sil. Foss. of Anticosti, p. 92. 

 Oystiphyllum Niagarense, Rominger. 1876. Geol. Sur. Mich., Fohs. Corals, p. 137, pi. 

 XLIX., fig. 3. 

 " Sherzer. 1892. A revision and monograph of the genus Ofcon- 



ophyllum ; Bull. Geol. 9oc. Amer., vol. 3, p. 266. 

 Lambe. 1899. Ottawa Naturalist, vol. XII,, p. 224. 



" The type specimen of C. Huronense is from the Niagara rocks of 

 Cockburn Island, Lake Huron, and was collected by Dr. R. Bell, in 1865. 

 Rominger has pointed out that Conophyllum Niagarense, Hall is in 



