Strophomena and Other Fossils 
115 
In a similar manner, I was not able to convince myself that 
the specimen from the Clay Cliffs, 3 miles north of Wekwemi- 
kongsing, on Manitoulin Island, resembling Strophomena nutans, 
(plate XI, Fig. 8) was not a variation of Strophomena huronensis, 
without any direct connection with the Ohio and Indiana speci- 
mens of Strophomena nutans. 
Strophomena acuta, Winchell and Schuchert^^ 
{Plate VII, Figs. 3 A, B, C, D; Plate IX, Figs. 13 A, B) 
Strophomena acuta was described as a variety oi' Strophomena 
neglecta, but it is evident from the exterior that it bears no resem- 
blance to that species, nor is it related to Strophomena incurvata. 
Strophomena incurvata and Strophomena neglecta belong to the 
group of Strophomena characterized by fine radiating surface 
striae, and by a rounded, flabellate muscular area in the pedicel 
valve. These features are not possessed by Strophomena acuta. 
Among the specimens figured in this Bulletin, none are the 
actual figured types, although they came from the type locality, 
in the Richmond group, at Spring Valley, Minnesota. The 
specimens represented by Figs. 3 A and B on plate VII, belong to 
the Schuchert collection; those represented by Figs. 3 C and D, 
are included in the set numbered 5550 in the collection belonging 
to the University of Minnesota, and all of them may be regarded 
as cotypes. 
General outline of the shell subtrigonal, the lateral outlines 
being moderately curved and converging from the cardinal angles 
toward the rounded anterior margins. Angle between the hinge- 
line and the general lateral contour of the shell 65 to 70 degrees; 
less commonly, 82 to 85 degrees. Valves usually wrinkled ob- 
liquely along the hinge-line. 
Brachial valve flattened for a distance of 8 to 10 mm. from the 
beak, thence evenly convex toward the anterior margin; slightly, 
almost imperceptibly concave anterior to the beak for about 2 
to 2.5 mm. 
Pedicel valve slightly convex near the beak. Greatest con- 
cavity about 12 to 13 mm. from the beak. 
Of the more prominent striae on the brachial valve about 6 or 
Minnesota Geol. Survey, vol. iii, p. 388, 1893. 
