AMNICOLA. 



81 



Operculum of 

 Amnicola. 



Fig. 159. sharp, not projecting anteriorly. Oper- 

 culum corneous. Foot rather short and 

 broad, expanded and broadly rounded 

 behind. Rostrum short. Tentacles 

 cylindrical, blunt at their tips. Verge 

 short, bifid, with a globular base. 



Ova-capsules serai-lenticular in form, with a 

 laminiform limb. Each contains but one effsr. 

 Station, fresh water. 

 Distribution, North America. (Sfimpson.) 



Fig. 160. 



Amnicola sayana, Anthony. — Sht'Ulengthenerl, conic, Fig. 161. 

 composed of six very convex shining whirls ; suture strongly ^ 



impressed ; lines of growth very fine ; base with a narrow um- f^ 



bilic ; aperture suhorbicular ; the labium slightly flattened, a X_y 



small portion of it in contact with the body whirl. Amnicola 



Color bright yellowish-browu, translucent. Inhabits south- sayana. 

 western Ohio. 



It is found on wet earth and roots of trees on the margin of a small 

 stream near Cincinnati. (^Haldeman.) 



Cyclostoma cincmnatiensis, Lea, Oct. 1S40, Proc. Am. Phil. S. I, 289 ; 

 1843, Tr. Am. Phil. Soc. VIII, 229, pi. vi. f. -62. 



Amnicola sayana, Haldeman, Mon. p. 19, pi. i, f. 11 (1844?) ; pt. 4, p. 

 4 of wrapper (1842) ; J. A. N. S. Phila. VIII, 200 (1842).— Anthony, 

 Cincin. Shells (1843), no desc. 



Paludina sayana, Kuster in Chemn. ed. 2, p. 49, pi. ix, f. 30 — 32. 

 J ChilocycJus cincinnatiensis, Gill, Proc. Phila. Ac. 1863, 34 (no descr.). 



Cyclostoma sayana, Jay, Cat. [4], 198 (1852), no descr. ; Amnicola,'^, 278. 



Troschel (Gebiss der Schnecken, p. 107, pi. viii, f. 1) figures the 

 lingual membrane of this species, and his figure is copied in my 

 figure 162; jSTo. 8934 of the collection is from Mr. Anthony. No. 

 8971 is labelled by Mr. Lea " Cyclostoma cincinnatiensis.''^ 



Found in Ohio and New York. 



This species was first described by Mr. Lea (in Oct. 1840) as 

 a Cyclostoma, under the specific name of cincinnatiensis. After 

 the true characters of the genus Amnicola had been recognized 

 by Gould and Haldeman, it became necessary to include in it 

 this species. It would then have borne the name of Amnicola 

 cincinnatiensis, had not the shell published in Jan. 1840, by Mr. 

 Anthony, as Paludina cincinnatiensis also been found to belong 



