1915] PALAEOZOIC FOSSILS FROM HuDSON Bay. 87 
is prominently marked by a longitudinal elevation which suffices for 
the determination of the species. 
The specimen shows a portion of the septate region only. Ina length 
of 40 mm. are 13 camere. At the fifth septum the dorso-ventral dia- 
meter is 22 mm. and the lateral diameter is 19 mm. The specimen is 
slightly distorted; a restoration would probably increase the dorso- 
ventral diameter. The sutures show a slight lateral lobe and a ventral 
saddle. The slow tapering, the lateral compression, the acute ventral 
shape, and the external siphuncle suggest the genus Ooceras as emended 
by Foord. 
The peculiar elevated ridge along the venter is quite characteristic 
and seems to justify a specific name. 
Locality—Drift of Nelson river, Manitoba. 
Horizon—Uncertain. 
No. 329 S. Royal Ontario Museum of Palaeontology. 
