1915] PALAEOZOIC FossILs FROM HupsoNn Bay. ay 
PHRAGMOCERAS WHITNEYI, Parks. 
Plate III, Figure 5; Plate VI, Figure 2. 
PHRAGMOCERAS WHITNEYI, Parks. Bur. Mines of Ont., 22nd Rep., pt. I, p. 194, 1913. 
This example is a remarkably large representative of the genus; in 
fact I have seen no greater figured. The species is founded on one cast 
of the chamber of habitation obtained by Mr. Tyrrell at the Limestone 
rapids, Severn river, and a portion of the septate shell found at Assina 
rapids on the same stream. There is no immediate proof that the two 
specimens belong to the same species, but the general agreement in 
size, the absence of more likely associations, and the similarity of the 
stone point to the identity of the two specimens. 
The dorso-ventral diameter of the shell at the anterior septum is 
108 mm. The lateral diameter at the same point is 30 mm., and it may 
possibly be a little greater, as one side of the cast is somewhat worn. 
The height of the body chamber is 130 mm., and the maximum width 
from ‘‘ear’’ to ‘‘ear’’ is 150 mm. The ventral margin of the body 
chamber is strongly concave and well extended towards the aperture. 
The dorsal margin is convex, but the curvature is less pronounced than 
on the concave side. The aperture is reduced to a narrow slit medially: 
on the ventral side it is about 25 mm. wide, and it is not preserved on 
the dorsal side. The maximum lateral diameter of the body chamber 
is 50 mm. The cast shows faint indications of vertical fluting with the 
furrows about 4 mm. apart. 
The first septum is strongly curved; a straight line joining the dorsal 
and the ventral extremities of this septum passes 27 mm. above the 
point of greatest curvature. 
The septate portion measured along the median line shows a length 
of 200 mm. but this by no means represents the whole length of the 
septate shell, as the specimen does not show the apex. In this length 
are 14 camere which do not indicate a lessening spacing of the septa 
towards the apex. The first and second camere are about 10 mm. 
high; the sixth and seventh are 15 mm. high; owing to breaking and the 
consequent impossibility of ascertaining the median line, the height of 
the more apicad camere cannot be given. 
This fine species is doubtless related to P. lineolatum, Whiteaves 
(Page 78), but it differs in the very much greater size and in the fact 
that the cross section does not show the attenuated ventral margin 
figured for P. lineolatum. 
The species is named for the late Honourable Sir James Pliny Whit- 
ney, Premier and President of the Council, Province of Ontario. 
Locality—Limestone rapids and Assina rapids, Severn river, District of Patricia, Ont. 
Horizon—Silurian. 
Nos. 318 and 319 S. Royal Ontario Museum of Palaeontology. 
