lambe. ] CANADIAN PALAEOZOIC CORALS. 149 



Hcliophyllum Eriense, Billings. 1859. Canadian Journal, new series, vol. IV., p. 124. 



Heliophyllum Cayugaense, Billings. 1859. Ibid, p. 124. 



Hcliophyllum Canaclense, Billings. 1859. Ibid, p. 125. 



Heliophyllum Halli, Billings. 1859 Ibid, p. 126. 



Heliophyllum Colbomense, Nicholson. 1873. Canadian Naturalist, new series, vol. VII., 



p. 143 ; and 1874, Palseon. of Ont., p. 25, pi. V., fig. 4. 

 Heliophyllum prol if cr urn, Nicholson. 1874. Geological Magazine, new series, vol. I., p. 



59 ; and 1874. Palseon. of Ont., p. 27. 

 Cyathophyllum Halli, Rominger. 1870. Geol. Sur. Mich., Foss. Corals, p. 98, pi. 



XXXV., four specimens in upper row. 

 Hcliophyllum Halli, Hall. 1876. Illus. Dev. Foss., pi. XXIII, figs. 1-5, 12 and pi. 



XXV., figs. 1-7. 

 Heliophyllum proliferum, Hall. 1876. Ibid, pi. XXVI., figs. 1, 2, 5. 



Corallum simple or by prolific budding becoming aggregate, broadly or 

 narrowly turbinate, conico-cylindrical or cylindrical, with many varia- 

 tions of these forms, straight, curved, twisted, or geniculated, frequently 

 contracted above, generally exhibiting numerous annular constrictions 

 and swellings, base small, pointed, the epitheca marked by numerous par- 

 allel rings of growth and striated longitudinally by distinct linear septal 

 furrows or depressions ; attaining a diameter of over 10 cent., and a 

 length of about 30 cent. Increase by lateral calicinal gemmation, some- 

 times as many as eight or nine buds springing simultaneously in a circle 

 from the sides of the calyx, Calyx with numerous modifications in shape, 

 in the short coralla, generally rather shallow with broadly expanding, more 

 or less reflexed margins, more inclined to become deep with steep sides in 

 the elongate forms, the sides radially ribbed by the free denticulated 

 edges of the septa that converge toward the bottom of the cup, where the 

 longer ones either meet with straight or twisted ends, at times uniting to 

 form a low boss, or falling short of the centre leave exposed a smooth 

 surface formed by the upper tabulum. A narrow septal fossette is pre- 

 sent in the cup. Septa of two orders, primaries and secondaries, the 

 former parsing to or almost to the centre, the latter reaching a little past 

 half way, strongly carinated on their side faces, the carina? curving up- 

 ward and inward from the wall, each corresponding pair forming, by 

 their union on the free edges of the septa in the cup, a prominent tooth- 

 like projection or short transverse rib : near the margin of the cup the 

 difference in size between the primaries and the secondaries is generally 

 not recognizable. The distance apart of the carina? from each other is 

 subject to considerable variation in different specimens and to a small ex- 

 tent in the same individuals, from four to twelve occurring in the space 

 of 5 mm. The septa number from about sixty-eight to one hundred in 

 specimens having a diameter of from 4 to 6 cent., in thicker specimens 

 sometimes as many as one hundred and fifty can be counted. Tabula? 

 small, flat in the centre, bent down at the edge, rendered vesiculose by 

 the introduction of cystose plates and generally somewhat disturbed in 



