[ 23 ] 

 15. Succinea lineata, W. G. Binney. 



Plate 2, figure 16. 



Oblong ovate, irregularlj wrinkled, between wliicb are 

 coarse, remote, revolving lines; spire acute; whoHs '6, very 

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

 ella folded. 



Length 12, diam. 6 mill. O^llT'^ (L?^- 0'^^-^ , 

 Nebraska, N. E. California, British America. 



Differs. from vermeta bj its more oval form. The aperture 

 is correctly egg-shaped. It is the heaviest of A merican 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 River. 



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 leno;th. 



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. C 



Differs from No. 16 principally in its diaphanous texture- 

 and dark '^o^nv. 



