38 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE. [VOL. XI 
HALYSITES CATENULARIA, Linnaeus. 
Plate V, Figure 6. 
TUBIPORA CATENULARIA, Linnaeus. Syst. Nat., ed. 12, p. 1270, 1767. 
HALYSITES CATENULARIA, Milne-Edwards and Haime. British Fossil Corals, p. 270, 
pl. LXIV, figs. 1, 1a, tb, 1c, 1850. (See this work extended 
synonomy.) 
HALYSITES CATENULARIA, Lambe. Geol. Sur. Can., Cont. to Can. Palaeon., Vol. IV, 
pt. L pyGs, pl. LIT, figs:'t,\1a, tbs 22a. saeoee 
HALYSITES CATENULATUS, Parks. Bur. Mines of Ont., 22nd Rep., pt. I, p. 196, 1913. 
This rather common Silurian coral is represented by two specimens 
from the Limestone rapids of the Severn and Fawn rivers. It is possible 
that a variety might be founded on the specimen from the Severn 
river, as it possesses remarkably wide connecting tubes between the 
corallites proper: these smaller tubes are filled with numerous, arched, 
overlapping, closely set, delicate tabule. The variety resembles H. 
catenularia nitida, Lambe (op. cit.) but it differs in the great irregularity 
of the tabule in the small tubes. 
Locality—Limestone rapids, Severn river; Limestone rapids, Fawn river, District of 
Patricia, Ontario. 
Horizon—Silurian. 
Nos. 337 and 338 S. Royal Ontario Museum of Palaeontology. 
PYCNOSTYLUS, Whiteaves. 
PycnostyLus, Whiteaves. Geol. Sur. Can., Palaeoz, Foss., Vol. III, pt. I, p. 2, 1884. 
Dr. Whiteaves’ original description of this genus is as follows: 
“Internal structure very similar to that of Amplexus, the radiating 
septa being rudimentary and extending but a short distance from the 
inner surface of the outer wall, but the tabule, though well developed 
and complete, are entirely horizontal, and neither bend upwards at 
the periphery nor embrace each other with their reflexed margins. 
Corallum compound, consisting apparently of an aggregation of numer- 
ous, slender, cylindrical or sub-cylindrical polyp stems, which divide 
by calicular gemmation at distant intervals into sets of three, four or 
more ascending, sub-parallel, contiguous, flexuous branches. Structure 
of the calices previous to gemmation, and character of the basal portion 
of the corallum unknown”’. 
Whiteaves describes two species, P. guelphensis and P. elegans: in 
the former the corallites are from 3 to 7 mm. in diameter and the epi- 
theca is marked by transverse constrictions but is without longitudinal 
septal furrows. In the latter species the corallites are from 13 to 17 mm. 
in diameter and the outer surface is regularly and longitudinally ribbed. 
