

1899] Lamijk — Canadian Paleozoic Corals. 247 



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 tabulpp. 



Locality and formation. — West Point, Grand Manitoulin 

 Island, Lake Huron, R. Bell, 1866, and Grand Manitoulin Island, 

 J. Townsend. 1883 ; Niagara formation. 



Clisiophyllum Billingsi, Dawson, sp. 



Cyathophyllum Billingsi, Dawson. 1868. Acadian Geology, 

 second edition, p. 287, fig. 84 b. 



Corallum simple, turbinate, evenly curved, annulated by 

 distinct ridges of growth, terminating above in a shallow 

 calyx ; nearly 5 cent, long as measured on the convex curve, 18 

 mm. broad near the top. Epitheca complete, thin, with very 

 fine, close-set, transverse growth lines and longitudinal septal 

 striae. Internally a narrow peripheral, vesicular area, in breadth 

 equal to about one-fifth the maximum diameter of the corallum 

 and made up of small convex plates arching upward and outward , 

 surrounds a broad inner zone of vesicles that are directed up- 

 ward and inward and fill the interseptal spaces, the centre being 

 occupied by a columella that appears at the bottom of the calyx 

 as a thin, laterally compressed projection. Septa about seventy- 

 two in number, of two sizes alternating with each other, the prim- 

 aries well developed, a few of them passing to the centre the re- 

 mainder almost reaching the centre, the secondaries very short. 

 In the calyx the secondaries appear only at the periphery but the 

 primaries are conspicuous as sharp-edged lamellas converging to- 

 ward the centre. On the surface where the epitheca has been re- 

 moved by weathering the outer edges of the two orders of septa 

 are exposed as longitudinal ribs of equal strength with the 

 horizontal edges of the vesicular plates filling the spaces between 

 them. 



Locality and formation. — Lower Stewiacke, county of Col- 

 chester, Nova Scotia, collected by Mr. C. F. Hartt ; lower 



