The Lcess and its Fossils. 207 



Stcccinea verrilli^ Bland. Veiy common. Specimens were 

 received from all of the localities cited. This species is closely 

 connected with S. avara by a large series of fossils. 



The majority of the specimens answer perfectly to the des- 

 cription and ligures of S. verrilJi given by Binney.' Some 

 are even more slender, with longer spire and smaller aperture 

 than shown by Binney's figures. Each of the larger sets of 

 fossils shows considerable variation. They somewhat resem- 

 ble the smaller form of S. avara which occurs on high or 

 comparatively dry ground, but all are more slender, with a 

 more elevated spire and smaller aperture than is possessed by 

 the latter. Some of the larger specimens are very similar to 

 medium-sized slender specimens of S. avara which were col- 

 lected in the vicinity of prairie ponds and streams in Marshall 

 county, Iowa, and Lancaster county, Nebraska. 



S. verrilli occurs at present in northern New England, and 

 on the islands of the Gulf of St. Lawrence. 



Siiccinca avara. Say. Large specimens of the preceding 

 species grade into a form which may be referred to this 

 species. It is not as common as the preceding and following 

 species, but is always associated with them. The present 

 range of this very variable species is throughout the northern 

 parts of the United States. 



Siiccinca lineata, W. G. B. A most abundant form, found 

 at all of the localities cited, is referred by the writer to this 

 species. It is usually identified as S. avara, but while equal- 

 ling or even exceeding in size the larger, river-bottom form 

 of that species, it has a more elevated spire, more convex 

 whorls, and a heavier shell, thus exactly resembling (as in all 

 other characters) Succinca which occurs commonly on the 

 prairies of Nebraska and Dakota, and which is ordinarily 

 identified as S. lincata, though comparatively few shells show 

 the revolving lines which characterize the types of the species. 

 Whether we regard this as a distinct species, or refer it to S. 



I In ^'T'vr. and Air Bvcaihing Moll, of the U. SP Vol. V., page 422. 



