420 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



it most resembles S. avara, but it differs in size and color. The shortest speci- 

 mens resemble S. campestris, but there is no fold of the columella. 



Succinea lineata, W. G. BINNEY. 



Shell oblong-ovate, with three very convex whorls ; spire elevated, acute ; 

 surface marked with irregular wrinkles of growth, between which 



Fl T > *-v7 o 



are coarse parallel revolving lines, somewhat removed from each 

 other ; aperture large, about as long as one half of the whole length 

 of the shell, oval; columella folded; a deposition of callus on the 



parietal wall of the aperture. Greatest diameter, 6 mill. ; altitude, 

 S. lineata. 



12 mill. 



Succinea lineata, W. G. BINNEY, Proc. Acad. Nat. Sci. Phila., 1857, 19 ; Proc. 

 Bost. Soc. Nat. Hist., VI. 155 (April, 1857) ; Terr. Moll., IV. 38, PI. LXXX. 

 Fig. 5 ; L. & Fr.-W. Sh., I. 262 (1869). TRYON, Am. Journ. Conch., II. 235 

 (1866). 



Fort Union, Nebraska Territory ; also in New Mexico, Arizona, and Sonora, 

 Mexico ; thus it belongs to both the Interior Region of the Eastern Province 

 and to the Central Province. 



The specimens collected being dead and eroded, it is impossible to say what 

 is the color of the shell when fresh. It is probably ashy-white, resembling 

 the true S. campestris of the Southern States. The revolving lines which dis- 

 tinguish it are most apparent on the middle of the body-whorl. These are 

 quite coarse, and placed at irregular intervals, on some specimens scarcely 

 discernible. The aperture is unlike that of any other of our species ; being 

 correctly egg-shaped, it is nearest in form to that of S. campestris, but is less 

 expanded. The parietal wall of the aperture is unusually horizontal. 



In general aspect it resembles somewhat S. vermeta, but is distinguished 

 from that shell by its more oval shape and the greater convexity of the whorls. 

 It is the heaviest American species. 



This species must not be confounded with S. lineata, DeKay. 



Jaw as usual ; no anterior ribs. 



The lingual membrane (PI. X. Fig. L) has 26126 teeth, with 4 perfect 

 laterals, but the transition to marginals is very gradual. The teeth have a 

 very broad base of attachment, and very slender, sharp cutting points. 



Succinea avara, SAY. 

 Vol. III. PL LXVII. c, Fig. 4. 



Shell rather small, very thin and fragile, straw-colored, rosy, amber-colored 

 or greenish ; periostraca shining, or presenting minute hairy processes in the 

 young ; whorls 3, very convex, separated by a deep suture ; last whorl rather 

 large, not much expanded ; spire very prominent, acute ; aperture ovate, 

 rounded at both extremities, about half as long as the shell. Extreme length, 

 about 6 mill. 



