"MBE. ] CANADIAN PALAEOZOIC CORALS. 157 



Genus Diphyphyllum, Lonsdale. 1845. 



Diphyphyllum, Lonsdale. 1845. Murchison's Geology of Russia in Europe, vol. I., 



p. 622. 

 Eridophyllum, Milne- Ed wards and Haime. 1850. Brit. Foss. Corals, p. lxxi. 

 Dipfophyllum, Hall, 1852. Palseon. New York, vol. II., p. 115. 



Corallum aggregate, composed of upright, subparallel, cylindrical cor- 

 allites with intervals between them, usually equal to or less than their 

 diameters and generally united by lateral, thorn-like, mural outgrowths. 

 Increase by lateral budding. Epitheca complete. Septa lamellar, straight, 

 their sides generally carinated, of two orders alternating, the primaries 

 seldom reaching the centre. Dissepirrents small, regular, arching con- 

 vexly upward and outward against the wall in the interseptal loculi, 

 usually in a single but sometimes in a double series. Tabuke numerous, 

 broad, stretching across the visceral chamber inside the dissepimental 

 zone, generally slightly deflected at the edge. No columella. No inner 

 wall. 



Type species. — D. concinnum, Lonsdale. 



Range. — Silurian, Devonian and Carboniferous. 



This genus differs from that of Cyathophyllum principally in its man- 

 ner of gemmation, in having lateral strengthening processes, in the 

 greater development of the tabulae, and in having the dissepiments in one 

 or two series only. From Crepidophyllum it is distinguished primarily 

 by the absence of an inner wall and in having proportionately larger 

 tabuhe and a smaller dissepimental area. 



The thorn-like spurs thrown out horizontally so as to reach or clasp 

 adjacent corallites do not connect the visceral chamber of one corallite 

 with that of another, as in the genus Syringopora, but serve as external 

 supports to the corallites to strengthen the growth of the corallum. 



In transverse sections of the corallites the cut edges of the regular and 

 equal sized dissepiments, when occurring in a single series, have the ap- 

 pearance of a second wall placed a short distance within the wall proper. 

 A second mural investment, however, such as is found in Crepidophyllum, 

 does not in reality exist. 



Diphyphyllum rugosum, Milne-Edwards and Haime. (Sp.) 



Eridophyllum? rugosum, Milne-Edwards and Haime. 1851. Polyp. Foss. des Terr. 



Pakeoz., p. 425, pi. 10, figs. 4, 4a, 4b. 

 Diphyphyllum rugosum, Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 121, pi. 

 XLV., fig. 2. 



Two specimens from the Niagara formation of Ontario are doubtfully 

 referred to this species. Their corallites are larger (averaging about 8 



