10 
MUSEUM BULLETIN NO. 29. 
slightly longer hingeline, more numerous central teeth, and lacks the fine 
radiating strise of the English species. The short hingeline, the curving 
down of the laterals, and the rounded outline place it in the genus Dicrano- 
donta. Height 42 mm., length 52 mm. This species is named -after D. B. 
Dowling. 
Horizon. Rare in the Peace River formation, Peace river, Alberta. 
Collection. Victoria Memorial Museum; holotype, Cat. No. 5395 ; - 
paratype, Cat. No. 5407. 
Genus, Nemodon Conrad. 
Nemodon mcconnelli n. sp. 
Plate III, figure 6. 
Description. Compared with the Coloradoan species Nemodon sulca- 
tinus E. and S., the Peace River form is a little smaller, proportionately 
longer, the anterior margin makes a right angle or more with the cardinal 
margin, and the well-defined sulcus of that species is lacking. The surface 
is ornamented by narrow, radiating, evenly spaced grooves, which are 
crossed by narrow, evenly spaced, concentric grooves; this forms a square 
network. 
N. vancouverensis Meek is much larger and has coarse radiating striae. 
The outline and ornamentation resemble that of Area murullensis d’Orbigny 
from the Neocomien and Aptien of France; but the Alberta species is 
much more convex and has more prominent beaks. Height 20 mm., 
length 23 mm. This species is named in honour of R. G. McConnell, 
Deputy Minister of Mines, Canada. 
Horizon. Rare in the Peace River formation, Peace river, Alberta. 
Collection. Victoria Memorial Museum; holotype, Cat. No. 5396. 
Family, Pinnid^: Meek. 
Genus, Pinna Linnaeus. 
Pinna curvimarginata n. sp. 
Plate IV, figure 1. 
Description. In size, proportional expansion, and angularity, this 
species resembles Pinna petrina White from the Coloradoan of New Mexico; 
but the ventral, not the dorsal, margin is concave and there are differences 
in the details of surface sculpture — the deflexion of the growth lines below 
the mesial angle is about midway between the latter and the ventral 
margin, and the rugose growth lines above the mesial angle are much more 
inclined to the convex dorsal margin. A few radiating striae are found 
below the mesial angle in the most anterior part of the shell. Height 75 
mm., length 200 mm. 
Horizon. Very rare (one specimen) in the Peace River formation, 
Peace river, Alberta. 
Collection. Victoria Memorial Museum; holotype* Cat. No. 5397. 
