EXPLANATION OF PLATE XXII. 



Cavoscala annclata Mort. sp. (p. 177). 



1<^1G8. 1, 2. Views of the opposite sides of a large specimen showing the general features. 



3. Basal view of the same specimen showing the character of the umbilical cavity and the 



flattened callosity around it. Acad. Nat. Sci., Phila. 



4. Enlargement of four of tlie ribs from the body volution. 



5. A further enlargement of one rib to show the finer vertical striae. 



Plel'rotomaria Tintonknsis Whitf. (p. 178). 



7-9. Vertical, basal, front and lateral views of the specimen described, which I am inclined to 

 think is a European specimen. Collection at Columbia College. 



Pleurotrema solariformis Whitf. (p. 180). 



10, 11. Vertical and basal views of a large individual from Ihe collection of the Am. Mus. Nat. 



Hist., New York City. 

 12, 13. Lateral and basal views of one from the collection of Acad. Nat, Sci., Phila. Fig. 12 



showing the casts of openings along the line of the slit, 

 14. View of a third specimen of the species. 



342 



