Figa 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
PLATE XIV. 
Legend. D. Deltidium. 
j. Cardinal process, 
s. Septum, 
b. Dental sockets, 
r, r'. Diductor scars. 
(Figures 1-22 by R. P. Whitfield.) 
Anterior adductors. 
Posterior adductors. 
Ovarian spaces. 
Vascular sinuses. 
Genus STROPHEODONTA, Hall. 
Page 284. 
STROPHEODONTA (DoUVILLINA) INiEQUISTRlATA, Hall. 
1, 2, 3. Three views, givingthe external characters of the species. 
4. The interior of a brachial valve. 
5. The central portion of the interior of the brachial valve, enlarged to show the broad, flat posterior 
muscular scars and the elevated anterior muscular ridges. X 3. 
6. The interior of the pedicle-valve, enlarged to show the muscular impressions. X 2. 
Hamilton group. Western New York. 
STROPHEODONTA DEMISSA, Coniad. 
7. The exterior of a pedicle-valve ; showing the fasciculate character of the surface striae near the beak. 
8. A view from the brachial valve of a larger individual; showing no evidence of deltidium on the 
striated cardinal area of the pedicle-valve. 
9. A profile view of the same. 
10. An enlargement of the cardinal areas ; showing the vertical striae and complete obsolescence of 
the deltidia. X 1|. 
11. The interior of a brachial valve; showing the crenulated hinge-margin, the cardinal process and 
muscular impressions. 
12. The interior of a pedicle-valve ; showing the muscular impressions. The center of the area has 
been broken away by the detachment of the cardinal process. 
Hamilton group. Western New York. 
STROPHEODONTA INiEQUIRADIATA, Hall. 
13. An internal cast of the pedicle-valve ; showing the muscular impressions and vascular sinuses. 
14. An enlargement of the umbonal portion of another cast; showing the dendritic diductor scars, the 
adductors, and, at k, the filling of the cavities occupied by the branches of the cardinal process. 
Comiferous limestone. New York. 
STROPHEODONTA PATERSONI, Hall. 
15. The exterior of a pedicle-valve; showing, over the visceral region, the undulations of the surface 
between the primary radii. 
Corniferous limestone. Western New York. 
STROPHEODONTA CONCAVA, Hall. 
Figs. 16, 17. Two views, to show the general external character of the shell. 
Fig. 18. The umbonal portion of the interior of a brachial valve. From a young individual in which the 
cardinal process is comparatively slender and the muscular area but slightly thickened. X 14- 
Hamilton group. York, N. Y. 
Fig. 19. The interior of the brachial valve ; showing the characters of the full-grown individual. 
Fig. 20. The central cardinal portion of the brachial valve of a mature individual. The lobes of the car¬ 
dinal process are of great size and deeply grooved, the crural plates in a rudimentary condition 
and the muscular scars much thickened. X 2. 
Fig. 21. A posterior view of the same specimen ; showing the crenulated edges of the cardinal lobes and 
the size of the crural plates. At x the base of the cardinal process has been excavated for the 
reception of the margin of the pedicle-valve. X 2. 
Hamilton group. Canandaigua Lake, N. Y. 
Fig. 22. The interior of a pedicle-valve ; showing a slight trace of the deltidium. 
Fig. 23. An internal cast of the pedicle-valve ; showing the adductor and diductor scars. 
Hamilton group. Western New Yor'k. 
