1915] PALAEOzOIC FossILs FROM Hupson Bay. 17 
The general shape of the shell and the strongly inflected anterior 
margin suggest the genus Lepiaena, but the concentric rugosities charac- 
teristic of that genus are not present. With no knowledge of the in- 
terior the form is provisionally referred to Strophomena. In the pre- 
liminary description the species was compared with S. julia, Billings,’ 
with which it is doubtless related. Billings’ species, however, has more 
numerous prominent striae or ribs, and instead of the concentric mark- 
ings between the major ribs it has fine radial striations. 
Locality—Lower rapids, Shamattawa river, Manitoba. 
Horizon—Ordovician. 
No. 403 S. Royal Ontario Museum of Palaeontology. 
RAFINESQUINA, Sp. indet. 
RAFINESQUINA LATA, Whiteaves, Parks. Bur. Mines of Ont., 22nd Rep., pt. I, p. 190, 
1913. 
The collection contains a fragment of a large Strophomenoid shell 
which bears some resemblance to Whiteaves’ species, but a close examin- 
ation indicates that its reference to that species is not justified. The 
shell was possibly 40 mm. long, but its width is not revealed. The 
specimen shows only the median portion of the pedicle valve, which is 
strongly arched from umbo to anterior margin and also transversely 
with a broad but faintly marked median fold. The striae are of two 
orders, fine and coarse, but there is no regular arrangement of the two 
kinds: in places they are not to be differentiated. The shell is punctate, 
and the cast of the interior is marked by vascular sinusus, particularly 
in the mid-anterior region. The brachial valve is concave and well 
set into the pedicle valve, but none of its structural features are revealed. 
The large size of this shell, its surface markings and its horizon 
suggest R. lata, but its arcuate outline, particularly in the transverse 
direction, seems to prohibit its reference to that species. The loss of 
the cardinal angles makes its specific identification doubtful, and I there- 
fore prefer to leave it for the present as an indeterminate species. 
Locality—Lower rapids, Shamattawa river, Manitoba. 
Horizon—Ordovician. 
No. 415 S. Royal Ontario Museum of Palaeontology. 
GASTROPODA 
HORMOTOMA ACUMINATA, Sp. nov. 
Plate IV, Figure 3. 
Hormortoma sp., Parks. Bur. Mines of Ont., 22nd Rep., pt. 1, p. 190, 1913. 
This species is founded on a cast of the interior showing five whorls. 
In the drawing the upper part of the spire is restored. 
1 Geol. Sur. Can., Palaeoz. Foss., Vol. I, p. 127, fig. 105a and b. 
pec 
