PLATE XXXVI 
Figs. 1 A, B. Elrodoceras indianense (Miller). A, ventral view showing 
the surface striae. B, opposite side of same specimen, showing the camerae, 
and the top of the siphuncle. From some locality in Indiana, in the upper 
part of the Laurel member of the Niagaran. Chief type of Rhynchor- 
oceras duhium Hyatt, numbered No. 2132, in the Museum of Comparative 
Zoology, at Harvard University. 
Figs. 2 A, B. Beloitoceras lycum (Hall). A, lateral view, cast of in- 
terior. B, ventral view. From Beloit, Wisconsin, in the Beloit member of 
the Black River. No. 999, in the American Museum of Natural History. 
Same specimen as Amer. Mus. Nat. Hist., Bull. 1, pt. 2, 1895, pL 9, figs. 13, 
14. See also Plate XLI, figs. 6 A, B, in this Journal. 
Figs. 3 A, B. Beloitoceras plebeium (Hall). A, lateral view, cast of in- 
terior. B, ventral view. From Beloit, Wisconsin, in the Beloit member of 
the Black River. Specimen numbered 996, in the American Museum of 
Natural History. Same specimen as that figured by Whitfield, in Bull. 
Amer. Mus. Nat. Hist., 1, pt. 2, 1895, pi. 9, figs. 18, 19. 
Figs. 4 A, B. Beloitoceras plebeium (Hall). A, lateral view, cast of in- 
terior. B, ventral view. From Beloit, Wisconsin, in the Beloit member of 
the Black River. Specimen numbered 996, in the American Museum of 
Natural History. Same specimen as that figured by Whitfield, in Bull. 
Amer. Mus. Nat. Hist. 1, pt. 2, 1895, pi. 9, figs. 15, 16. See also Plate XLI, 
figs. 5 A, B. 
Figs. 5 A, B. Beloitoceras pandion (Hall). A, lateral view, cast of in- 
terior. B, ventral view. From Beloit, Wisconsin, in the Beloit member of 
the Black River. Specimen numbered 998, in the American Museum of 
Natural History. Same specimen as that figured by Whitfield, Bull. Amer. 
Mus. Nat. Hist., 1, No. 2, pi. 9, figs. 21, 22. See also Plate XLI, figs. 4A, 
B, C. 
The lines over figures 3A and 4A indicate the probable outline of the 
aperture on lateral view. 
