THE NATURAL HISTORY SURVEY. 335 



Length, 4.00; width, 2.00; aperture length, 1.50; width, 1.10 mill. (10497.) 



Animal and Radula: Similar to A. limosa. 



Distribution: New York to Illinois and Minnesota. (Pils- 

 bry.) 



Geological distribution: Pleistocene. 



Habitat: Same as A. limosa. 



Remarks: This species is distinguished from all others of 

 the genus by its narrow, elongated whorls and rather acute 

 spire. It is said by Mr. Pilsbry to be the narrowest of the 

 genus. Lustrica does not seem to be at all common and has 

 only been found at Berry Lake and Joliet. 



SUBGENUS CINCINNATIA, Pilsbry, 1891. 

 Proc. Phil. Acad.. p. 327, 1891. 



Radula more minute and denticulations finer than in the 

 typical form. 



136. Amnicola cincinnatiensis Lea, pi. xxvi, fig. 14. 



Cyclostoma cincinnatiensis LEA, Proc. Amer. Phil. Soc., I, p. 289, 1840; 

 Trans. Amer. Phil. Soc., VIII, p. 229, pi. vi, fig. 62, 1843. 



Amnicola sayana ANTHONY, in HALDEMAN, Mon., p. 19, pi. i, fig. 4, 

 1844? (Figs.4 and 11 are misnamed in Haldeman; 4 is the present 

 species and 11 is Pomatiopsis cincinnatiensis Anthony.) 



Shell: Of good size, swollen, umbilicated, rather solid; 

 color ranging from greenish to yellowish-brown, translucent; 

 surface smooth and shining, lines of growth well developed, 

 crowded; sutures forming deep channels between the whorls; 

 apex small, rounded, smooth, brownish; spire broadly conic, ele- 

 vated; whorls five to six, rapidly increasing, swollen, rounded, 

 the last somewhat loosely coiled so that the aperture is continu- 

 ous and separated from the body-whorl; aperture roundly ovate, 

 bluish-white within; peristome continuous, simple, thin, sharp, 

 appressed to the body-whorl only at the upper part; base 

 rounded, with a small, rounded umbilicus of great depth. 



Length, 5.00; width, 4.00; aperture length, 2.00; width, 1.75 mill. (10653.) 

 5.50; " 4.00; " " 2.00; " 1.75 " (10653.) 



Animal: Yellowish-white above, whiter on base of foot; 

 subtransparentjfoot short and wide, auriculated before, rounded 

 behind and constricted in the center; operculigerous lobe and 

 operculum as in limosa; rostrum short; tentacles long and slen- 

 der, blunt; eyes, mantle and verge as in limosa. 



Radula formula: T V+iV-f t+^ir+i+A+fr (3 - * - 3); 

 (Mus. No. 12769); central tooth similar to that of limosa, but ends 



