174 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



zone formed of a system of vertical or twisted lamellae and of vesicular 

 tabulae ; the median zone formed of large vesicles made up of horizontal 

 plates ; the peripheral zone filled with a very fine vesicular tissue. Sil- 

 urian to Carboniferous." (Zittel : Traite de Paleontologie.) 



Clisiophyllum Billingsi, Dawson. (Sp.) 

 Plate XIV., figs. 10, 10a. 



Cyathophyllum Billingsi, Dawson. 1868. Acadian Geology, second addition, p. 287, fig. 



846. 

 Clisiophyllum Billingsi, Lambe. 1899. Ottawa Naturalist, vol. XII., p. 247. 



"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. Ep- 

 itheca complete, thin, with very fine, close-set, transverse growth lines and 

 longitudinal septa stride. 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, sur- 

 rounds a broad inner zone of vesicles that are directed upward and in- 

 ward 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 primaries well developed, a few of them 

 passing to the centre, the remainder 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 lamellae con- 

 verging toward the centre. On the surface where the epitheca has been 

 removed 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. — Lower Stewiacke, county of Colchester, Nova Scotia, col- 

 lected by Mr. C. F. Hartt ; Lower Carboniferous. One specimen, the 

 property of the Peter Redpath Museum, McGill University, Montreal." 

 (Lambe, 1899. 



Genus Acrophyllum, Thomson and Nicholson. 



Acrophyllum, Thomson and Nicholson. 1876. Ann. and Mag. Nat. Hist. , fourth series, 

 vol. XVII., p. 455. 



Generic characters. — "Corallum simple, turbinate, or cylindro-conical. 

 Epitheca thin, with numerous encircling striae and annulations of growth. 

 Central area occupied by strong tabulae, which are not vesicular, and are 



