72 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE. [VOL. XI 
CEPHALOPODA 
ENDOCERAS HUDSONICUM, Parks. 
Plate V, Figure 10. 
ENDOCERAS HUDSONICUM, Parks. Bur. Mines of Ont., 22nd Rep., pt. I, p. 195, 1913. 
This species is founded on one broken and very unsatisfactory 
fragment. A restoration of the outline presented by the fragment 
would indicate an elliptical shell about 110 mm. by 75 mm. Although 
the specimen is broken and probably somewhat deformed, I am of the 
opinion that the shell was elliptical rather than round. 
The septa are rather closely placed for a shell of this size—about 
7 mm. apart: at a point where the siphuncle is 20 mm. from the shell 
the septa extend 20 mm. forward to their sutures. 
The siphuncle is apparently round and about 35 mm. in diameter; 
it is within 20 mm. of the shell on one side and 50 mm. at 90°. Direccly 
opposite to the first measurement the distance cannot be ascertained. 
The siphonal funnels are tubular and reach almost if not quite to the 
septum next apicad. 
Vertical sections show considerable displacement of the funnels 
and the complete absence of an inner sheath or other endosiphuncular 
structures. In view of the fragmentary nature of the specimen it is 
perhaps unwise to establish a species but the inaccessible nature of the 
locality of occurrence must serve as an excuse for so doing. I am further 
impelled to this action by the fact that the genus Endoceras is rare if 
not absent among Silurian Cephalopoda hitherto described. It should 
be noted however that Whiteaves records the occurrence of Endoceras 
or Nanno from the Silurian rocks of the Ekwan river. We are perhaps 
dealing with the same species referred to by him on page 263, Volume 
III of Palaeozoic Fossils. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 322 S. Royal Ontario Museum of Palaeontology. 
ORTHOCERAS (?), sp. indet. 
One small fragment of a brevicone, but worthy of mention because 
quite distinct from any other form in the collection. 
Shell circular, 13 mm. in diameter at anterior end. In a length of 
10 mm. it decreases to a diameter of 7mm. Septa about I.5 mm. apart. 
Sutures straight. Siphuncle not observed. Shell absent. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 341 S. Royal Ontario Museum of Palaeontology. 
