246 College of Forestry 



Amnicola oneida Pilsbry. 



The shell is typically more slender than A. lustrica, turrited- 

 conic, narrowly iimbilicate, corneous, minutely striate. The 

 apex is slightly obtuse, but the first whorl projects visibly, as 

 in lustrica, whorls ver}^ convex, parted by a deep suture. The 

 aperture is ovate, small, its length contained more than three 

 times in that of the shell, upper extremity narrowly rounded. 

 The peristome is continuous, thin, very briefly in contact with 

 the preceding whorl above. 



Length 4, diam. 2, length of aperture 1.25 mm. ; 6 whorls 



Lower South Bay, Oneida Lake, N. Y., collected by F. C. Baker, 



1916 

 [Cotypes, New York State College of Forestry, No. QSse] 

 Lower South Bay, west of steamboat landing, water 4 feet deep, 



sandy bottom covered with algae. 



This species is typically narrower than A. lustrica Pils., 

 with a smaller aperture and shorter whorls, but it is chief!}' 

 distinguished by the more convex whorls (deeper suture) 

 and the rounded instead of angular posterior end of the aper- 

 ture. In Paluderstrina nickliniana the last whorl is much 

 longer. Possibly it may be a subspecies of lustrica, yet it 

 has so distinct an appearance that a special name seems desir- 

 able. There are also wide examples, which still differ from 

 lustrica by the deeper suture and aperture. 



Reprinted, with bracketed additions, from 

 " The Nautilus ", Vol. 31, pp. 44-46, 1917- 



