1915] PALAEOZOIC FOSSILS FROM HupsoN Bay. 83 
cular tissue. The intermediate ones in the section appear longer than 
they are in the cup. A longitudinal section shows the vesicular plates 
arched a little upwards in the middle under the boss, then downwards 
and again inclined upwards in the outer area in two or three rows of 
cells. In these sections both the lamella and the transverse plates 
are thin, and the former are wavy,” 
Localities—Drift, Mouth of the Nelson river; Drift, Mouth of Machichi river; Assina 
rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian? 
Nos. 294 S., 295 S., 296 S. Royal Ontario Museum of Palaeontology. 
PHRAGMOCERAS NELSONENSE, Sp. nov. 
Plate I, Figure 7; Plate III. Figures 1 and 2. 
This species is founded on four fragments showing living chambers 
and one showing a portion of the septate shell. 
The dimensions of the living chamber at the anterior septum are 
as follows in the different specimens: 
I 2 3 4 
Dorso-ventral diameter.... 25 mm. AoQrmiarey yee 25 mm. 
Lateral diameter......... 19 mm. 19 mm. 19 mm. 18 mm. 
The height of the body chamber in the median line is from 30 to 
35 mm. In no case is the outer shell preserved, but some of the casts 
show a bead-like ornamentation of the posterior margin with faintly 
marked longitudinal ribs extending upward therefrom. Both the ventral 
and the dorsal outlines of the living chamber are convex. The dorsal 
aperture is much the larger and the ventral aperture much smaller 
and situated at the extremity of a sharply drawn out, tube-like pro- 
longation of the shell. 
The septate region is rather sharply curved ventrally just beyond 
the living chamber, but the whole form of the septate shell is not re- 
vealed. The anterior septa on the dorsal margin are about 2.5 mm. 
apart. On the ventral side, they are slightly closer together and present 
.a faint ventral saddle. 
The siphuncle is small and is situated close to the ventral margin. 
The indications of vertical fluting on the living chamber suggest 
P. nestor canadense, described by Dr. Whiteaves from the Guelph 
formation at Hespeler, Ont.! The present example, however, is much 
smaller, the dorsal aperture is more extended and the septate region is 
more curved. 
1 Geol. Sur. Can., Palaeoz. Foss., vol. III, p. 39, pl. 7, figs. 1, 1a and 1b. 
