PLATE XXVIII. 



PAGE 



Fig. 1. Natica cliftonensis Clark 150 



Ventral view of type specimen. Clifton Beach. 



Figs. 2, 2a, 3. Lunatia marylandica Conrad 151 



Figs. 4, 5. Calypteaea aperta (Solander) 152 



4. Dorsal vie^v of specimen. 1 mile southeast of Mason Springs. 



5. Cast of large individual. 



Figs. 6, 6a. Litiopa marylandica n. sp 152 



6. Dorsal view of type specimen. 2 miles below. Potomac Creek. 



Figs. 7, 7a. Solarium sp 153 



7. Cast, as seen from above. Aquia Creek. 

 7a. Same specimen as seen from the side. 



Figs. 8, 8a, 9, 9a. Scala virginiana Clark 153 



8. Ventral view of tj^pe specimen. Aquia Creek. U. S. National 



Museum. 

 8a. Dorsal view of same specimen. 



9. Ventral view of specimen. Potomac Creek. Acad. Nat. Sci. Phila. 

 9a. Dorsal view of the same specimen. 



Fig. 10. Scala potomacensis n. sp 154 



Type sjiecimen. 2 miles below Potomac Creek. 



Fig. 11. Scala sessilis Conrad 154 



2 miles below Potomac Creek. 



Fig. 12. Scala carinata Lea 154 



2 miles below Potomac Creek. 



280 



