OF CONCHOLOGY. 235 



15. Succinea lineata, W. G. Binney. 



Plate 2, figure 16. 



Oblong ovate, irregularly wrinkled, between wliicli are 

 coarse, remote, revolving lines ; spire acute ; whorls 3, very 

 convex; aperture one-half the length of the shell, oval; colum- 

 ella folded. 



Length 12, diam. 6 mill. 



Nebraska, N. E. California, British America. 



Differs from vermeta by its more oval form. The aperture 

 is correctly egg-shaped. It is the heaviest of American spe- 

 cies. The columella is not always folded, nor the revolving 

 lines apparent. 



16. Succinea Mooresiana, Lea. 



Plate 2, figure 17. 



Ovate, thin, striate ; spire elevated, acute ; whorls 3, convex, 

 suture impressed ; body large, not inflated ; aperture widely 

 ovate, obtusely angled above ; columella with a distinct fold. 

 Light yellowish- white. 



Length 9, diam. 6 mill. 



Platte Eiver. 



This may be only a variety of No. 15. The principal differ- 

 ence is, that it is more depressed, the spire not so much 

 exserted and not so convex, and the aperture nearly two-thirds 

 the total length. 



17. Succinea Oregonensis, Lea. 



Plate 2, figure 18. 



Elongated oval, thin, diaphanous, shining, striate ; spire 

 acute, suture well impressed ; whorls 3, well rounded ; body 

 seven-eighths and aperture two-thirds the total length ; aper- 

 ture ovate, one-third longer than broad, columella arcuate. 

 Color deep orange or golden. 



Length 9, diam. 6 mill. 



Oregon, California. 



Differs from No. 16 principally in its diaphanous texture 

 and dark "oW. 



