uhk.] CANADIAN PALAEOZOIC CORALS. 169 



PHILLIPSASTRiEA BlLLINGSI, Calvin. 



Phillipsastrcea gigas, Billings. 1859. Canadian Journal, new series, vol. IV., p. 128; 

 incorrectly identified with Arachnophyllum (Astrea ?) gigas, 

 Owen. 

 .i n Nicholson. 1875. Palseon. of Ont., p. 77. 



Phillipsastrea gigas (?), Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 128, pi. 



XXXVII., fig. 4. 

 Phillipsastrea billingsi, Calvin. 1893. American Geologist, vol. XII., p. Ill, pi. VI., 



figs. 1 and 2. 

 Phillipsastrcea Billingsi, Lambe. 1899. Ottawa Naturalist, vol. XII., p. 249. 



"Corallum composite, large, discoidal, more or less convex above, 

 rather flat below, formed of slightly divergent, confluent, polygonal coral- 

 lites, from about 2 to over 4 cent, in diameter, that increase by marginal 

 calicinal gemmation from a central basal beginning ; attaining a breadth 

 of over 40 cent, and a height of nearly 12 cent. Basal surface covered by 

 a concentrically wrinkled epitheca. Corallites not bounded by a wall, 

 their septa meeting and becoming confluent with those of neighbouring 

 corallites ; opening on the upper surface in calyces having a broadly con- 

 vex, exsert, reflexed circular rim surrounding a deep, steep-sided pit 

 measuring from about 8 to 10 mm. in diameter, and 4 or 5 mm. deep. 

 Septa well developed, numbering from about forty to sixty, of two alterna- 

 ting sizes, the larger reaching the centre and becoming somewhat twisted, 

 or falling short of it, the smaller not extending beyond the sides of the 

 central pit ; they are decorated on their sides by arched carinae curving 

 upward and inward and appearing on their free edges in the central pit 

 and reflexed calicinal margins as small transverse denticulations. Tabulae, 

 forming a narrow axial area, at times well developed, flat at the centre, 

 turned down at the edge, the primary septa passing over them to the 

 centre as carinae, at other times, interfered with by the septal ends which 

 cut into them and destroy their horizontal continuity, giving them more 

 the character of dissepiments than of tabulae. Dissepiments filling the 

 interseptal spaces and curving upward and outward in regular order, those 

 in the peripheral region being generally larger than those nearer the centre; 

 they are pierced at their junction with each other by oval or circular 

 pore-openings forming a uniserial row midway between the septa." 

 (Lambe, 1899.) 



Locality and formation. — Corniferous limestone of Ontario. 



Genus Pachyphyllum, Milne-Edwards and Haime. 1850. 

 Pachyphyllum, Milne-Edwards and Haime. 1850. Brit. Foss. Corals, p. lxviii. 



" Corallum astraeiform ; septa numerous, well developed, reaching the 

 centre and passing over the wall. Calyces marked by strongly developed 

 exothecal tissue. Devonian" (Zittel : Traite de Paleontologie). 



