PLATE 29. 
Figs. 1 - 8. Spirifera oweni... 
1. Dorsal view of a young specimen. 
2. Dorsal view of a larger individual. 
3-7. Dorsal, ventral, cardinal, profile and front views of a specimen of ordinary size and char¬ 
acteristic form. 
8. Interior of a part of a ventral valve. 
Page 
197 
Fig. 9-18. Spirifera acuminata. 198 
9. Front view of a young individual, from New York. 
10 - 13. Dorsal, ventral, cardinal and profile views of a specimen of ordinary size and form, 
from near Sandusky, Ohio. 
14. Front view of a small hut extremely elevated specimen, from Williamsville, N. Y. 
15. Cast of a ventral valve, showing the muscular impression of greater width than usual; from 
Albany county, New York. 
16. 17. Yentral and cardinal views of a cast in chert, from Camp Creek, Ind., showing muscu¬ 
lar impressions, dental cavities, etc. The mesial elevation has been injured by weather¬ 
ing, and the outline shows the probable extent of the elevation. 
18. Dorsal view of a specimen from the same locality as the preceding, showing the peculiar 
muscular markings of the dorsal valve. 
