40 LIMNEA COLUMELLA. 



and in this case, the shells are difficult to dis- 

 tinguish from those of some species of Succinea. 

 They differ very much among themselves; and, 

 in some instances, approach L. auricularia in 

 form. ; L. macrostoma' appears to me to be 

 nothing more than a variety with a well ex- 

 panded aperture; a distorted individual, in fact, 

 (fig. 6) having been a 'columella' until it sud- 

 denly assumed the macrostomous form in the 

 body whirl. 'L. succiniformis,' Adams, MS., I 

 refer to this species. Say alludes to a variety 

 which he found in Missouri, and which, judging 

 from its color, must be identical with the 

 variety 'chalybea.' To be obtained in perfec- 

 tion, this species must be sought for early in 

 the spring. 



REFERENCE TO PLATE 12. 



Figures 13 15 represent the original 'L. columella;' 

 1 5 'L. macrostoma;' 9 <L. chalybea;' and 8, 10 12 a 

 shining delicate variety, which may be considered a dis- 

 tinct species by some. 



