162 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



projecting but little inside of the single row of curved dissepiments in 

 the interseptal spaces. In transverse sections of the corallites the dissepi- 

 ments have the appearance of an inner wall about *5 mm. distant from 

 the wall proper, as in the Silurian species D. ccespitosum, Hall. Tabulae 

 well developed, flat, horizontal, bent slightly down at their edges ; from 

 ten to fifteen in a space of 5 mm. 



"This species is somewhat similar, in its internal structure, to D. 

 ccespitosum, Hall, from which it differs principally in having shorter and 

 less numerous septa. 



" The coral from the Devonian (American Stringocephalus zone) of 

 Dawson Bay and vicinity, Lake Winnipegosis, described by Dr. Whit- 

 eaves (op. cit. pp. 270 and 271), and referred to by him as bearing 

 * a remarkably close resemblance in size, shape and internal structure ' 

 to ' the Diphyphyllum straminium of Billings,' is here referred to D. 

 Simcoense, with which the writer considers D. stramineum to be con- 

 specific, a view already expressed by Dr. Rominger in his excellent work 

 on fossil corals/' (Lambe, 1899.) 



Locality and formation. — Abundant in the Corniferous limestone of 

 Ontario. 



Diphyphyllum arundinaceum, Billings. 

 Plate XIV., figs. 1, la, lb. 



Diphyphyllum arundinaceum, Billings. 1859. Canadian Journal, new series, vol. IV., 

 p. 134. 



Nicholson. 1874. Palseon. of Ont., p. 32, pi. VI., fig. 1. 

 Diphyphyllum — (?) compare D. arundinaceum and D. stramineum, Billings. Whiteaves. 

 1877. Rep. of Progress for 1875-76, Geol. Survey of Canada, p. 102. 



Found in large colonies of long, flexuous, cylindrical corallites, that 

 vary in diameter from 6 to 10 mm. and are separated from each other by 

 spaces equal to or less than their diameters. Of the mode of increase and 

 of the size attained by the coralla, Mr. Billings, in his original description 

 of the species, says : — " The young corallites sometimes spring from the 

 side of the parent, with a slender base, and curving upwards immediately, 

 become parallel with those of the whole group. In large colonies frequent 

 instances may be seen where, instead of this lateral budding, a bifurcation 

 takes place, both branches being of the same size. In large groups, owing 

 to the numerous additions of young, the corallites diverge slightly, as if 

 radiating from a point. The colonies are from six inches to several feet 

 in diameter, and large blocks of stone are of frequent occurrence, which 

 are penetrated at right angles to the stratification by the closely crowded 

 stems." Corallites free from sudden constrictions, provided with a well- 



