Figs. 32 to 35. 
32 and 33. 
34 and 35. 
Figs. 36 to 40. 
36. 
By( 
38. 
39. 
40. 
Fig 41. 
ANASTROPHIA (?) HEMIPLICATA, Var. ROTUNDA, D. var 
Views of the ventral and dorsal valves respectively. 
Profile and anterior views of the same.specimen. Galena shales, near Cannon 
Falls, Minn. Minnesota Geological Survey collection. 
STEOPHOMENA ENOURVATA Sheppard. iSp:ssenins ct. seam aueilesee oe oo cae cee aeclecies 
Dorsal view of a very convex specimen in which the strie are nearly of equal size. 
Profile view of the same specimen. The dotted line indicates the curvature of 
the ventral valve. Trenton shales, Lanesboro, Minn. 
Interior of a well preserved ventral valve, showing the muscular scars, genital 
markings and vascular sinuses. Trenton shales, Minneapolis, Minn. Collec- 
tion of C, Schuchert. 
The interior of a dorsal valve, showing the cardinal processes, dental sockets, 
genital markings and vascular sinuses. Trenton shales, St. Paul, Minn. 
Profile outline of a less gibbous specimen than fig. 37. Lower Blue beds, Dodge- 
ville, Wisconsin. Minnesota Geological Survey collection. 
STROPHOMENA TRENTONENSIS, D. Sp............-- FCO one Oe nT En 
The interior of a ventral valve. Trenton shales, Minneapolis, Minn. Minnesota 
Geological Survey collection. 
385 
389 
