1915] PALAEOZOIC FOssILS FROM HUDSON Bay. 27 
the septa and the funnels appear to be double in correspondence with 
the general character of Actinoceras. 
The endosiphuncle tapers rapidly, showing a diameter of 35 mm. at 
the anterior end and 12 mm. at the posterior end: its surface is finely 
striated longitudinally and it is drawn out into ridges between the 
septa. Tubuli arise from or near these ridges and pass directly out- 
ward into the nummuloidal rings which they appear to penetrate. The 
rapid tapering of the endosiphuncle is a feature not described for A. 
richardsont, and constitutes a second reason for establishing a variety. 
The nummuloidal rings are somewhat irregularly developed, but are 
fairly evenly rounded, filling the whole interseptal space, and with the 
septa in contact with their posterior aspect for a considerable distance 
outwards. 
Calcareous deposits form concretionary layers around the septal 
necks. Similar material is deposited around the endosiphuncle with 
the result that, with the shrinking of the endosiphuncle posteriorly, 
the whole space between the endosiphuncle and the siphuncle is filled 
with dense calcareous tissue. 
I regard this specimen as related to A. richardsoni for the following 
reasons: The average septal spacing, the calcareous investment of the 
endosiphuncle, the somewhat irregular development of the nummu- 
loidal rings, the well marked endosiphuncle, the strongly arched septa, 
and the direct outward course of the tubuli. 
A distinct variety is indicated by the following points: The rela- 
tively greater width of the siphuncular segments to their height, the 
relatively smaller siphuncle compared with the width of the shell, and 
the rapidly tapering endosiphuncle. This latter fact may, however, be 
due entirely to the fact that our specimen probably represents a portion 
of the shell just posterior to the living chamber. 
Locality—Mouth of Shamattawa river, Manitoba. 
Horizon—Ordovician. 
No. 309 S. Royal Ontario Museum of Palaeontology. 
HURONIA SEPTATA, Sp. nov. 
Plate V, Figure 8. 
Our collection contains one broken siphuncle presenting part of 
the exterior and a longitudinal section which unfortunately is not 
median. 
The fragment is 112 mm. long and shows six segments, making the 
average height of the segment 18.66 mm. The outline of the ring is a 
sigmoidal curve with the broader part anterior. The greatest diameter 
of the anterior ring is 40 mm. and the least diameter 28 mm. 
