285 



32. CYCLAS INORNATA Nolis. Bost. S. N. H. Proc. iv. 159. 

 Cabinet of the Ac. Nat. Sc. 



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



Locality. Illinois, (Haldeman.) 



One dead valve of this species is all that has, as yet, been 

 found. 



Compared to the C. similis^ it is less elongated ; the lateral 

 margins are less rounded, the cardinal teeth are also more rudi- 

 mentary. 



33. CYCLAS DISTOETA Nolis. Bost. S. N. H. Proc. iv. 158. 

 Cabinet of the B. S. N. H. 



Shell Vide Bost. S. N. H. Proc. iv. 158. 



Localities. Ohio, (Adams and Agassiz.) Maryland, (Fore- 

 man.) 



This shell has been confounded with *C. similis ; it is, how- 

 ever, more compact, broader, less equilateral, less elongated ; 

 the hinge margin is more spherical. Compared to the C. soli- 

 dula, it is more elongated, the margins are less rounded, the stria- 

 tions are heavier and more irregular, and the coloring is dif- 

 ferent. 



34. CYCLAS TENUIS Notts. Bost. S. N. H. Proc. iv. 161. 

 Cabinet of the B. S. N. H. 



Shell Vide Bost. S. N. H. Proc. iv. 161. 



Localities. Massachusetts ? (Stimpson.) Androscogoin, Me. 

 (Girard.) 



This species closely resembles the young of C. transversa ; 

 it differs, however, in being more inflated and less elongated ; 

 it is broader in latitude. 



35. Ci-CLAS PATELLA Gould. Bost. S. N. H. Proc. iii. 293. 



Shell. Vide Bost. S. N. H. Proc. iii. 293. 



Locality. Oregon, (Gould.) 



This is to be compared with C. cornea, on account of the 



