1915] PALAEOZOIC FossILS FROM HupDsON Bay. 39 
The following statement is significant: “It is possible that the specimens 
for which the above name (P. elegans) is provisionally 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’’. 
Our collection contains twelve specimens in an indifferent state of 
preservation, none of which show any features other than those of the 
ordinary portions of the corallites, z.e., there is no evidence of the bifur- 
cations, point of attachment or calyx. The average size of the corallites 
varies greatly, but they may be arranged in five groups as follows: 
Diameter of ues average 5 mm.—Two specimens. 
re ae iy 7 mm.—One specimen. 
9 mm.—Two specimens. 
16 mm.—Five specimens. 
25 mm.—Two specimens. 
In all the specimens the actual substance of the corallite—epitheca, 
septa, and tabule seems to be of extreme tenuity, and the preservation 
in each case is due to secondary deposits of calcite. Specific differentiation 
on the basis of mere size is very hazardous, and lacking epithecal charac- 
teristics we are deprived of the second means of identification. On the 
whole, however, it seems advisable, provisionally at least, to ascribe 
the 5 and 7 mm. types to P. guelphensis; the 9 and 16 mm. types to 
P. elgans, and to make a new species for the 25 mm. type. 
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PYCNOSTYLUS GUELPHENSIS, Whiteaves. 
AMPLEXUS LAXATUS, Billings. Geol. Sur. Can., Rep. 1863, pp. 340 and 342, 1863. 
AMPLEXUsS? sP., Nicholson. Palaeontology of Ontario, p. 66, 1875. 
PYCNOSTYLUS GUELPHENSIS, Whiteaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. 1, 
p. 3, pl. I, figs. 1, 1a and Ib, 1884. 
PYCNOSTYLUS GUELPHENSIS, Whiteaves. Ibid., pt. II, p. 49, 1895. 
PYCNOSTYLUS GUELPHENSIS, Lambe. Geol.Sur. Can. Cont. to Can. Pal., Vol. IV, pt. 2, 
p. 132, pl. X, figs. 4 and 4a, 1900. 
PYCNOSTYLUS GUELPHENSIS, Parks. Bur. Mines of Ont., 22nd Rep., p. 193, 1913. 
Three specimens containing in all about 40 corallites which vary in 
diameter from less than 5 to slightly more than 7 mm. The tabule 
are rather more widely spaced than in the type, for our specimens seldom 
show more than 4 tabule in a centimetre, whereas Whiteaves recog- 
nizes from 5 to 9 in his types. The absence of longitudinal ribs on the 
exterior, a characteristic of P. guelphensis, is clearly indicated by at 
least one of the corallites. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 301 S. Royal Ontario Museum of Palaeontology. 
