iamm. ] CANADIAN PALAEOZOIC CORALS. 171 



mer converging to the centre where they generally meet and are fre- 

 quently twisted, the secondaries about one-quarter the length of the 

 primaries ; both sizes of septa start inward at an equal distance from the 

 centre, the primaries becoming suddenly thin and continuing so for the 

 inner half of their length. Outer zones of neighbouring corallites by their 

 union forming a continuous vesicular tissue surrounding and separating the 

 septal cycles. The convex plates forming the vesicles incline slightly 

 upward toward the septa, continue for some distance inward and down- 

 ward as dissepiments in the interseptal loculi and becoming larger and 

 flatter at the centre of the visceral chamber form an axial area of irregu- 

 lar tabulae. 



Locality. — Peace River, Athabasca District, Prof. J. Macoun, 1875 ; 

 Devonian (Cuboides zone). 



Genus Blothrophyllum, Billings. 



Blothrophyllum , Billings. 1859. Canadian Journal, new series, vol. IV., p. 129. 



Generic characters — " Corallum, simple, turbinate or cylindrical. 

 Internal structure, consisting of a central area occupied by flat, transverse 

 diaphragms, an intermediate area with strong radiating septa, and an 

 outer area in which there is a set of imperfect diaphragms project- 

 ing upwards, and bearing on their upper surfaces rudimentary radiating 

 septa. A thin complete epitheca and a septal fossette. Generic name 

 from Greek (2Aa>0p6s" (Billings). 



Type species. — B. decortication, Billings. 



Range. — Devonian. 



Blothrophyllum decorticatum, Billings. 



Plate XV., figs. 1, la. 



Blothrophyllum decorticatum, Billings. 1859. Canadian Journal, new series, vol. IV., 



p. 130, fig. 25. 

 i, „ Nicholson. 1874. Palaeon. of Ont., p. ; 19, pi. IV., fig. 3. 



ii .. Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 112, 



pi. XLI. 



Corallum simple, conico-cylindrical, long and flexuous, pointed and 

 conical at the base, cylindrical above, strongly annulated at short and 

 rather regular intervals by growth markings representing the rims of 

 former calyces, reaching a thickness of over 7 cent., one specimen having 

 a diameter of between 4 and 5 cent, and a length of over 40 cent, 

 although imperfect at both ends. Calyx of moderate depth, with broad 



