283 



25. Cyclas aurea Nolis. Bost. S, N. H. Proc. iv. 159. 

 Cabinet of the B. S. N. H. 



Shell Vide Bost. S. N. H. Proc. iv. 159. 



Locality. Lake Superior, (Agassiz.) 



This is a rare and beautiful species. In outline it is some- 

 what like the C. si?nilis, but otherwise it is different. Its very 

 much curved hinge margin renders it distinct from any other 

 shell. 



26. Cyclas acuminata Nobis. Bost. S. N. H, Proc. iv. 155. 



Cabinet of the B. S. N. H. 

 Ci/clas albula Nobis. Bost. S. N. H. Proc. iv. 155. 



Shell Vide Bost. S. N. H. Proc. iv. 155. 

 Locality. Lake Superior, (Agassiz.) Ohio, (Ingalls.) 

 Compared to the C.Jiava^ this species is larger, more robust, 

 and of a different color. 



27. Cyclas emarginata Kalis. Bost. S. N. H. Proc. iv. 156. 



Cabinet of the B. S. N. H. 



Shell Vide B. S. N. H. Proc. iv. 156. 



Locality. Lake Superior, (Agassiz.) 



Compared to the C. acuminata., this species is smaller, more 

 oblique ; the hinge margin is more curved, and the lateral teeth 

 are more prominent ; the coloring and outline are different. 



28. Cyclas bulbosa Anthony^ Mss. 

 Cabinet of T. Prime. 



Shell Not large, short, thick, globose, spherical ; posterior 

 margin somewhat abrupt ; anterior and inferior ones rounded ; 

 beaks large, prominent, well rounded ; lines of growth not deep, 

 but irregular; color yellowish green ; interior light blue ; hinge 

 margin curved ; cardinal teeth nearly obsolete ; lateral ones not 

 very prominent ; posterior tooth the more elongated. 



Long. 0.3S ; lat. 0.33 ; diam. 0.28 inches. 



Locality. Arkansas, (Anthony.) 



