FAMILY TURBINIDjE AMNICOLA. 87 



P. subcarinala. (Say, Nich. Ency. p. 1, fig. 7. Hald. pi. 2.) Whorls three, rounded and subcarinate, 

 reticulated with stria? and wrinkles (sometimes no stria;); suture deeply impressed; apex trun- 

 cated and reentering; aperture oval, more than half the length of the shell: 2-3, and sometimes 

 more, elevated lines or subcarina on the body. Length, 0*5; breadth, 0-4. Pennsylvania. 



P. limoniUfera. (Lea, Am. Tr. Vol. 5, p. 58, pi. 19, fig. 71.) Shell obtusely turreted : apex obtuse. 

 Whorls with two rows of nodules: those of the lower row of the upper whorls hidden by the suture; 

 of the upper row larger, and visible on all the whorls: suture deep and irregular: outer lip sub- 

 biangular; base subangular. Color, dark horn. Height, 1*8; diameter, 1 • 1 . Alabama River. 



GENUS AMNICOLA. Gould and Haldeman. 



Animal with the foot rounded behind, and each anterior angle laterally produced. Head half 

 the breadth of the foot, and protruding beyond it. Tentacles short, filiform, unequal? 

 Eyes at the side of the external base. Oviparous. Fluviatile. Shell ovate-conic, thin ; 

 spire acute, composed of a few rounded whorls ; aperture small, oblique, rounded-ovate ; 

 lip continuous simple. Opercle horny, spiral, with a few volutions. 



Obs. This genus has been established by Messrs. Gould and Haldeman, for the reception 

 of a few small shells hitherto classed under Paludina, but with distinct habits. Its position 

 seems to be between Paludina and Melania. 



Amnicola lustrica. 



Paludina lustrica. Say, Journ, Acad Nat. Sc. Vol. 2, p. 175. 



P. id. Adams, American Joum. Science, Vol.40, p. 267. Valvala pupoidea ? 



Description. Shell small, conic. Whorls slightly wrinkled, convex : suture profoundly 

 indented ; aperture oval, nearly orbicular ; lip with the upper edge not appressed to the 

 preceding whorl, but simply touching it: umbilicus rather large, rounded. Length, 01 

 nearly. 



This very small species was first detected by Mr. Jessup, on the shores of Cayuga lake. 

 It abounds also in the streams emptying into Lake Champlain. 



