336 



THE CHICAGO ACADEMY OF SCIENCES. 



supporting only two denticles, and a bulge near the lower end; 

 process on concave margin large; intermediate tooth of the 

 usual shape, but the denticles longer and narrower than in 

 limosa and the central denticle rounded and blunt, the others 

 sharp; inner and outer lateral teeth denticulated as in limosa 

 (Fig. 121). The figure of this species in Binney's "Land and 

 Fresh Water Shells" (Fig. 162), taken from Troschel, must be an 

 error, for it does not at all correspond with the specimens ex- 

 amined by the writer, which are undoubted cincinnatiensis . 

 The species is peculiar in having the cusps of the intermediate 

 tooth long and sharp, and in the central cusp being wide and 

 blunt. The figure in Binney's is probably the radula of some 

 Pomatiopsis, perhaps P. lapidaria* 



FIG. 121. 



Radula of AMNICOLA CINCINNATIENSIS Lea. (Original.' 

 tooth; I, intermediate tooth. 



C, central 



Distribution. New York to Utah, south to Texas. 

 Geological distribution : Pleistocene. 

 Habitat: Same as limosa 



Remarks: This is the largest species of Amnicola found 

 in this region and attains a length of five or six mill. Its large 

 size, swollen whorls, and elevated co|iic spire will at once dis- 

 tinguish it from related species. It is rather common, espe- 

 cially at Joliet, where it is the prevailing species. 

 137. Amnicola emarginata Kuster, pi. xxvi, fig. 10. 



Paludina obtusa LEA, Proc. Amer. Phil. Soc., Vol. II, p. 84, 1841, non 



Troschel, 1837. 



Paludina emarginata KUSTER, Paludina, Conch. Cab., p. 50, pi. x, figs. 

 3, 4, 1852. 



*It should be noted here that the present figure is drawn to a larger scale than that of 

 the radula of Amnicola limosa. The radula of A. cincinnatiensis is smaller and the den- 

 ticulations are smaller, narrower and sharper than in A. limosa. 



