40 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE. [VOL. XI 
PYCNOSTYLUS ELEGANS, Whiteaves. 
Plate I, Figure 3. 
PYCNOSTYLUS ELEGANS, Whiteaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. I, p. 4, 
pl. I, figs. 2, 2a, 1884. 
PYCNOSTYLUS ELEGANS, Whiteaves. Ibid., pt. II, p. 49, 1895. 
PycCNOSTYLUS ELEGANS, Lambe. Geol. Sur. Can., Cont. to Can. Pal., Vol. IV, pt. II, 
p. 133, 1900. 
PYCNOSTYLUS ELEGANS, Lambe. Cruise of the Neptune, p. 326, 1906. 
PYCNOSTYLUS ELEGANS, Parks. Bur. Mines of Ont., 22nd Rep., p. 193, 1913. 
The specimens ascribed to this species vary from 9 mm. to more 
than 16 mm. in diameter. Most of the specimens are embedded in 
matrix and show only the internal characters. One specimen, probably 
decorticated, shows longitudinal ribbing and transverse striations. 
Another small specimen has the epitheca excellently preserved: its 
structure tends to confirm the identification and to strengthen Whiteaves’ 
conclusions as to the specific difference of P. elegans. This epitheca 
(Pl. I, Fig. 3) shows delicate and fairly even transverse ridges, which 
are more crowded in some parts than in others. Vertical ridges or ribs 
are also well marked, and correspond in position with the very short 
septa. In the finer specimens (9 mm. diam.) the tabule are about 
3 mm. apart, for the most part flat, but slightly arched in places. This 
smaller form might, with equal reason, be ascribed to P. guelphensis. 
The larger specimens show much variation in the spacing of the tabule: 
generally they are from 3 to 4 mm. apart, but in one instance an interval 
as great as 14 mm. separates them. In view of the extreme delicacy of 
the original tabule, and the consequent opportunities for destruction, 
too much reliance must not be placed on this feature. In this specimen 
also, the tabulze are arched and slightly crenulated at the margins. 
There is also some indication of two orders of septa, which is a feature 
not,admitted by Whiteaves in his description of the type. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 302 S. Royal Ontario Museum of Palaeontology. 
PYCNOSTYLUS MAXIMUS, sp. mov. 
Plate I, Figure 2. 
This species is represented by two small fragments only, but they 
are sufficiently different from the known species to justify their reference 
to a new type. 
The corallites attained a diameter of at least 25 mm. and probably 
exceeded that size in some cases. Although the specimens are very 
