78 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE. [VOL. XI 
PHRAGMOCERAS LINEOLATUM, Whiteaves. 
PHRAGMOCERAS LINEOLATUM, Whiteaves. Geol. Sur. Can., Ann. Rep., Vol. XIV, pt. F, 
P. 57, 1904. 
PHRAGMOCERAS LINEOLATUM, Whiteaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. IV, 
p. 265, pl. 34, figs. 1, Ia, 2 and 3, 1906. 
PHRAGMOCERAS LINEOLATUM, Parks. Bur. Mines of Ont., 22nd Rep., pt. 1, p. 195, 1913 
This species is probably represented by three specimens—one show- 
ing a chamber of habitation, and two exhibiting parts of the septate 
region. 
Our specimens are large, slightly exceeding in size the largest one 
figured by Whiteaves. At the anterior septum our specimen measures 
64 by 40 mm. The septa are I1 mm. apart on the convex or dorsal 
margin, and only 3 mm. apart on the ventral margin. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 317 S. Royal Ontario Museum of Palaeontology. 
PENTAMEROCERAS RARUM, Sp. nov. 
Plate III, Figure 6. 
One small specimen showing the body chamber with part of the 
test preserved. The character of the aperture is well shown by the 
cast of the interior, which projects beyond the preserved portion of the 
shell. 
The chamber of habitation is of elliptical shape, with a maximum 
diameter of 18 mm. and a minimum diameter of 15.5 mm. The shell 
contracts rapidly towards the aperture, producing a narrow hyponomic 
sinus, a median dorsal sinus and two lateral sinuses. The cast of the 
hyponomic sinus indicates a length of 12 mm.; the median sinus a length 
of 5 mm.; and the lateral sinuses lengths of 4.5 mm. (ventral) and 6 mm. 
(dorsal). 
The test shows delicate, flexuous, transverse striations. 
The type of the genus Pentameroceras, Hyatt, is Gomphoceras nurum, 
Barr. (Systéme Silurien de la Bohéme, Pl. 478, Fig. XII, 1 and 2. PI. 82, 
Figs. 17-25; Pl. o1, Figs. 7-14; Texte, Vol. 11, Partie IV, p.134-))3tne 
type of aperture characteristic of this genus seems to be extremely rare, 
for Barrande states ‘‘Cette forme de l’ouverture n’a été observée que 
dans une seule espéce, Gomphoc. mirum de la Bohéme. . .. Tous ces 
specimens ont été trouvés sur l’horizon de notre bande e2; les 3 petits, 
4 Hinter-Kopanina et les 3 plus grands, 4 Lochkow”’. 
Our species is remarkably like P. mirum and is comparable with the 
larger forms figured by Barrande. The most noticeable difference is 
