CANADIAN PALEOZOIC CORALS. 



133 



corallite and to fill the entire visceral chamber where, by their pressure 

 on each other, they are at first angular but diverging slightly they rise 

 as complete cylindrical corallites each in turn to subdivide again. The 

 largest specimen in the collection, representing a corallum of greater size, 

 is rougly 17 cent, high and 16 cent, broad. 



Pycnostylus elegans, Whiteaves. 



Pycnostylus elegans, Whiteaves, 1884. Palaeoz, Fobs., vol. III., pt. I., p. 4, pi. L, figs. 

 2, 2«. 

 Whiteaves, 1895. Ibid, pt. II., p. 49. 



Original description. — " Corallites attaining to a diameter of from 13 

 to 17 mm.: increasing by calicular gemmation in such a manner as to divide 

 into six or seven branches on the same plane : external surface regularly 

 and longitudinally ribbed, the ribs alternating with the septa within : all 

 the septa of uniform length and size. 



" The only specimen of this coral in which calicular gemmation is 

 plainly visible is presented by figure 2 on plate 1 (op. cit.). Part of 

 this specimen is covered with rock, but on the exposed surface five buds 

 are visible, one of which is an inch and a quarter long, while the other 

 four are broken off at their bases. Judging by the diameter of the buds 

 in proportion to that of the calyx from which they spring, it is probable 

 that the entire cycle would consist of either seven or eight. 



" It is possible that the specimens for which the above name is pro- 

 visionally suggested may prove to be portions of the basal extremity of 

 P. Guelphensis denuded of their epitheca, but at present no intermediate 

 examples between the two forms have been collected." 



Localities and formation. — Hespeler, Ont., T. C. Weston, 1867; Dur- 

 ham, Ont., Mr. J. Townsend. Guelph limestone. 



The number of septa in mature corallites of this larger form varies 

 from about forty-five to fifty-five and there are four or five tabulae in a 

 space of 1 cent. 



CYATHOPHYLLID^E. 



Genus Cyathophyllum, Goldfuss. 1826. 



Cyathoplyllum, Goldfuss. 1826. Petrefacta Germanise, vol. I., p. 54. 

 Heliophyllum, Hall. 1848. U. S. Explor. Exped., Zooph., Dana. 



Coralium simple, aggregate or astrteiform. Increase by calicular gem- 

 mation. Epitheca complete. Septa regularly radial, lamellar, well 

 developed, generally in two alternating sizes, primaries and secondaries 

 the former sometimes reaching the centre of the visceral chamber where 



