The Nautilus. 



Vol. XXVI. MAY, 1912. No. 1 



A NEW SPECIES OF AMNICOLA. 



BY H. A. PILSBRT. 



Amnicola winkleti, n. sp, Plate I, figs. 9, 10. 



The shell is umbilicate, ovate-conic, composed of 4^ to nearly 5 

 strongly convex whorls, separated by a very deep suture ; whitish 

 corneous when cleaned of the thin brown stain, glossy, faintly striate ; 

 apex rather acute, aperture ovate, nearly vertical ; peristome contin- 

 uous, a little flattened where it is very shortly in contact with the 

 proceeding whorl. 



Length 4.8, diam. 3.1 mm.; length of aperture 2.2 mm. 



Saco, Maine. 



By its dentition this species belongs to the group of Amnicola 

 lustrica Pils., the shape of the central tooth and its denticulation 

 being quite unlike A. limosa. It differs from limosa by its projecting 

 first whorl, that of limosa being flat on top. A lustrica is smaller 

 and more slender. A schrokingeri Ffld. is closely related but is a 

 very much smaller species. Frauenfeld gives the length as 3.15 

 mm., and the largest in a series of over 100 before me is 3.2 mm, 

 long, with 4^ whorls. 



A. winkleyi has some resemblance to A. (^Cincinnati a^ cincinnati- 

 ensis Anth. by its acute apex and very convex whorls, but it is less 

 solid, and differs very widely in dentition. 



This species is one of the fruits of the careful examination of the 

 New England fauna by the Rev. Henry W. Winkley, during the 

 past decade or more. Doubtless the species exists in many collec- 

 tions under one name or another. My attention was called to it in 

 the course of a study of the northern species for a monograph of the 

 New York fauna. 



