iavbe] CANADIAN PALAEOZOIC CORALS. 175 



very strongly elevated centrally, and at the same time more or less 

 twisted with a spiral bending, so as to give rise to a central funnel-shaped 

 and obliquely contorted eminence. This eminence is formed solely by the 

 elevation of the successive tabulae ; and no vertical plates take part in its 

 formation as is the case in Clisiophyllum, The septa are well developed, 

 lamellar, usually prolonged over the upper surfaces of the tabulae in the 

 form of striae which extend nearly to the centre. External area traversed 

 by the septa, which are united by comparatively remote angular dissepi- 

 ments. No columella. A well-marked septal fossette." (Thomson and 

 Nicholson.) 



Type species. — A. (Clisiophyllum) Oneid&ense, Billings. 



Range. — Devonian. 



Acrophyllum Oneidaense, Billings. (Sp.) 



Plate XVI., figs 1 and 2. 



Clisiophyllum Oneidaense, Billings. 1859. Canadian Journal, new series, vol. IV., p. 128. 



ii ii Nicholson. 1874. Palaeon. of Ont., p. 20, pi. IV, figs. 4 and 5. 



Acrophyllum Oneidaense, Thomson and Nicholson. 1876. Ann. and Mag, Nat. Hist. 



fourth series, vol. XVII., p. 455. 

 Clisiophyllum Oneidaense, Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 109, pi. 



XL, upper row. 



Corallum simple, conico-cylindrical, pointed below and generally 

 curved for a short distance above the base, at first turbinate then becom- 

 ing cylindrical and often somewhat flexuous or bent, attaining a length 

 of over 36 cent, and a thickness of about 6 cent. ; one specimen measures 

 6 cent, in diameter not more than 8 cent, above the base. Annulated by 

 numerous strong and decided wrinkles of growth and provided with an 

 epitheca marked by minor transverse linss of growth and longitudinal septal 

 furrows corresponding to the primary and secondary septa beneath. The 

 surface for a distance of 5 or 6 cent, from the base is often decorated by 

 numerous transverse rows of spinous outgrowths up to 2 or 3 mm . in 

 length. Calyx deep, with a sharp rim and steep sides, in which the free 

 edges of the septa appear as thin lamellae surrounding a prominent, 

 conical, twisted boss that rises abruptly from the bottom ; from about 

 one-third to nearly one-half the diameter of the coral in depth. A nar- 

 row fossette is present in the bottom of the cup. Septa numbering from 

 about one hundred in slender specimens, to over one hundred and ninety 

 in large individuals, of two orders, primaries and secondaries, alternating, 

 the latter so small as to be almost obsolete, the former strong, cutting the 

 edges of the tabulae, a variable number passing over the tabulae as carinas, 

 some reaching, others falling short of the apex of the central boss and all 

 partaking of the twist of that prominence. Tabulae well developed, form- 



