iamu.] CANADIAN PALEOZOIC CORALS. 185 



of the tabuhe as carinas, the secondaries not infringing on the tabulae ; 

 beyond the confines of the central pit their vertical coniinuitv is interrupted 

 and they radiate outward as gradually broadening, flatly convex ribs, 

 reaching a maximum breadth of 2 mm. at the edge of the calycinal 

 extension where they meet the septal ribs of adjacent calyces. Pore- 

 openings in the septal ribs have not been recognized in specimens belonging 

 to this species. The vesicular structure supporting the calycinal floors, 

 developed at intervals in the upward growth of the colony, is composed 

 of blister-like plates that are proportionately rather smaller and less 

 convex than in other species of the genus, also the radially folded caly- 

 cinal floors appear to be developed with greater frequency and are 

 consequently closer together than in A. pentagonum, Goldfuss, from 

 which this species differs in many essential points. Between the lamellar 

 septa arched dissepiments curve downward to meet the tabuke." (Lambe, 

 1899.) 



Locality. — West Point, Grand Manitoulin Island, Lake Huron, R. Bell, 

 1866, and Grand Manitoulin Island, J. Townsend, 1883; Niagara formation. 



Genus Chonophyllum, Milne-Edwards and Haime. 1850. 



Chonophyllum, Milne-Edwards and Haime. 1850. Brit. Foss. Corals, p. lxix. 



Corallum simple, short and broadly expanded or by the superaddition 

 of successive calycinal expansions becoming conico-cylindrical. Calyx 

 steep-sidel with expanded horizontal or reflexed margins. Central area 

 irregularly tabulate with a convex calicular surface. Peripheral area 

 broad, vesicular. Septa sometimes reaching the centre, thin and con- 

 tinuous vertically in a cycle surrounding the tabulae where they are of 

 two sizes, but in the peripheral expansion developing into superficial and 

 equal, rounded ribs that unite laterally so as to form a laminar surface- 

 covering to the supporting vesicles. 



Type species. — C. (Cyathophyllum plicatum) perfoliatum, Goldfuss. 

 Upper Silurian (Niagara) of the Island of Gotland, Sweden. 



Range. — Silurian, Devonian. 



Chonophyllum Canadense, Billings. (Sp.) 

 Plate XVII, figs, 1, la, lb, lc, 2, 3, 3a, 3b and 4. 



Ptychovhyllum Canadense, Billings. 1862. Palaeoz. Foss., vol I., p. 107. 



Billings. 1866. Cat. Sil. Foss. of Anticosti, p. 34. 

 Chonophyllum Canadense, Lambe. 1899. Ottawa Naturalist, vol. XII., p. 222. 



"Corallum Jarge, circular, much broader than high, expanding laterally 

 from a small, obtusely pointed base into a broad, thin, frill-like, horizontal 



