PLATE XIV. 



Atrypa aspera. 



Fig. 1-5, 7-11. A series of specimens showing variations in form and 



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Fig. 6. Interior of a ventral valve. 



Atrypa reticularis. 



Fig. 12-17, 19. A series of specimens showing variations in form and 



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Fig. 18. Dorsal view of a specimen, broken so as to show spiral cones. 

 Fig. 20. Ventral view of a specimen, broken so as to show spiral cones. 

 Fig. 21. Side view of a specimen, broken so as to show spiral cones. 

 Fig. 22. View of a single spiral cone. 

 Fig. 23. View of interior of a ventral valve. 



