78 
IOWA ACADEMY OF SCIENCE Vol. XXIX, 1922 
PLATE I 
Rhynchotrema kentuckiense varians var. nov. 
1-3. Brachial, pedicle, and lateral views of the holotype. 
Rhynchotrema wisconsinense sp. nov. 
6-8. Brachial, pedicle, and lateral views of the holotype, showing the 
lamellae. 
Rhynchotrema decorahense sp. nov. 
9-11. Brachial, pedicle, and lateral views of the holotype, the last 
showing the great depth of the pedicle valve. 
Rhynchotrema cuneiforme sp. nov. 
12-14. Brachial, pedicle, and lateral views of the holotype. 
Rhynchotrema minnesotense (Sard.) 
15-17. Brachial, pedicle, and lateral views of a plesiotype. 
Rhynchotrema kentuckiense sp. nov. 
4. Brachial view of a small paratype, showing the long, pointed 
beak. 
5. Lateral view of another paratype, showing the shallowness of 
both valves during the earlier stages of development. 
18-19. Brachial and pedicle views of the holotype. 
20. Lateral view of the holotype; cf. fig. 5. 
21-22. Brachial and pedicle views of a paratype. 
(All figures enlarged about 1.5 diameters) 
