24 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 78 



Page 

 Figures 7, 8. Aphrodina? aspenana Reeside and Weymouth, new species. 



U.S.N.M. Cat. No. 73768 9 



7. Plaster cast from the holotype, a natural mold of the exterior 

 retaining parts of the shell. 



8. Plaster cast from the paratype, a natural mold of the exterior. 

 Figure 9. Linearia? species, a natural cast of the exterior. U.S.N.M. Cat. 



No. 73769 9 



Figure 10. Thracia? wyomingensis Reeside and Weymouth, new species, 



the holotype, a natural cast of the exterior. U.S.N.M. Cat. No. 73766- 8 



Figure 11. Mactraf aspenana Reeside and Weymouth, new species, view 



(X 2) of a plaster cast from the holotype, a natural mold of the exterior. 



U.S.N.M. Cat. No. 73772 11 



Figures 12, 13. Mactraf incompta White? U.S.N.M. Cat. No. 73771--. 10 



12. View (X 2) of a plaster cast from a natural mold of the exterior 

 of a right valve. 



13. Plaster cast from a natural mold of two right valves. 



Figure 14. Kanabiceras aspenanum Reeside and Weymouth, new genus 

 and species, plaster cast from the holotype, a natural mold of the exte- 

 rior. U.S.N.M. Cat. No. 73773 12 



Figure 15. Epengonoceras aspenanum Reeside and Weymouth, new species, 

 plaster cast from a paratype, a natural mold of the exterior. U.S.N.M. 

 Cat. No. 73774--_- ". 16 



Plate 2 



Figure 1. Metoicoceras species, plaster cast from a natural mold of the 



exterior. U.S.N.M. Cat. No. 73778 22 



Figures 2-5. Epengonoceras aspenanum Reeside and Weymouth, new 



species. U.S.N.M. Cat. No. 73774 16 



2. Plaster cast from a paratype, a natural mold of the exterior. 

 3-5. Side view, parts of several sutures (X 2) at a diameter of 60 mm., 



part of a suture (X 3) at a diameter of 50 mm. of the holotype, a 

 flattened mold of the interior preserving parts of the shell. Several 

 imprints of Ostrea species are also shown. (See p. 6.) 



Plate 3 



Figures 1-4. Acompsoceras americanum Reeside and Weymouth, new 

 species, two side views, peripheral view, and suture (X 2) of the holo- 

 type, a distorted internal mold of part of a whorl. U.S.N.M. Cat. No. 

 73775 18 



Figures 5-7. Epengonoceras aspenanum Reeside and Wej^mouth, new 



species, U.S.N.M. Cat. No. 73774 16 



5. Plaster cast from a paratype, a natural mold of the exterior. 



6, 7. Side and peripheral views of a paratype, a fragmentary^ internal 

 mold preserving the venter. 



Figure 8. Metoicoceras ivhitei Hyatt, view of a small internal mold. U.S. 



N.M. Cat. No. 73776 22 



Plate 4 



Figures 1-7. Metoicoceras whitei Hyatt 22 



1, 2, 5, 6. Four plaster casts from natural molds of the exterior. U.S. 

 N.M. Cat. No. 73776. 



3, 4, 7. Three plaster casts from natural molds of the exterior, from 

 another locality. U.S.N.M. Cat. No. 73777. 



k U. S. GOVERNMENT PBINTJNG OFFICE: 1931 



