EXPLANATION OF PLATE XLI. 



Unless otherwise mentioned, all the figures on this plate are X 15, and are 



copied from Ulrica. 



Figs. 1-3. Drepanella Mgeneris Ulrich. 



1. Side view of left valve. 



2. Posterior view of same valve. 



3. Longitudinal sectional view across the central part of the same. 

 4-6. Drepanella crassinoda Ulrich. 



4. Side view of right valve. 



5. Dorsal view of same valve. 



6. Posterior end view of complete carapace. 

 7,8. Drepanella nitida (Ulrich). 



7. Left valve of an average complete specimen. 

 S. Ventral view of same. 



9. Drepanella ampla Ulrich. 

 Lateral view of right valve. 

 10,11. Drepanella elongata (Ulrich.) 



10. Left valve. 



11. Longitudinal sectional view. 

 12-14. Drepanella macra Ulrich. 



12. Side view of right valve. 



13. Longitudinal and vertical sectional views across central part of same 



valve. 



15. Drepanella richardsoni (Miller). 

 Side view of a left valve (original). 



16-18. Scofleldia bilateralis (Ulrich). 



16. Side view of a right valve of the usual appearance. 

 17, IS. Ventral and posterior views of a left valve. 



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