66 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE. [VOL. XI 
callosity which shows some evidence of being hollow, as it is bounded 
by shelly matter and filled with crystalline calcite; it is more likely, 
however, that the calcite has partially replaced the substance of the 
callosity. The second whorl shows a distinct thickening of the shell 
on the inner side, but a pronounced callosity as in the basal whorl is 
not observed. The specimen is much too imperfect for specific deter- 
mination, but it appears to belong to the genus Pycnomphalus, and 
undoubtedly represents an undescribed species. 
Locality—Assina rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 368 S. Royal Ontario Museum of Palaeontology. 
GYRONEMA DOWLINGII, Whiteaves. 
GYRONEMA DOWLINGII, Whiteaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. IV, 
p. 259, pl. 29, fig. 3, 1906. 
GYRONEMA DOWLINGH, Parks. Bur. Mines of Ont., 22nd Rep., pt. 1, p. 193, 1913. 
The species is represented by one broken cast which is sufficiently 
distinct to leave little doubt of the identification, and by several frag- 
ments of smaller individuals. 
Locality—Above Limestone rapids, Severn river, District of Patricia. 
Horizon—Silurian. 
No. 354 S. Royal Ontario Museum of Palaeontology. 
Cf. GYRONEMA SPECIOSUM, Whiteaves. 
GYRONEMA SPECIOSUM, Whiteaves. Geol. Sur. Can., Ann. Rep., Vol. XIV, pt. F, p. 50, 
1904. 
GYRONEMA SPECIOSUM, Wiiewbe Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. IV, 
p. 258, pl. 29, fig. 2, 1906. 
GYRONEMA SPECIOSUM, Parks. Bur. Mines of Ont., 22nd Rep., pt. 1, p. 193, 1913. 
One fragment of a body whorl probably referable to this species. 
The ornamentation of the under side of the whorl is like that of G. 
speciosum, but near the periphery the revolving ridges are distinctly 
wider spaced. The ornamentation of the upper side is not preserved. 
The specimen may represent a variety of G. speciosum, but it is much 
too imperfect for description. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 370 S. Royal Ontario Museum of. Palaeontology. 
A second specimen of very small size shows only a portion of one 
whorl, but it presents the ornamentation of G. speciosum in a manner 
which admits of less doubt in its determination. 
No. 375 S. Royal Ontario Museum of Palaeontology. 
