476 LIMN^ID.E. 



bee, i. 196. — W. G. Binnet, Smith. Inst. L. and Fr. W. Shells, II. 44, figs. 60 - G6 



(1865). 

 Limncm NuttalUana, Lea, Pr. A. P. S. ii. 33 (1841) ; Tr. Am. Phil. Soc. ix. 9 (1844) ; 



Ob.s. ii. 9. — KiJSTER (Limmeus), in Chemn. 2d ed. 38, pi. 7, fig. 5. 

 Limncea plebeia Gould ? (see below.) 

 Limncea expansa, Haldeman, Mon. 29, pi. 9, figs. 6-8 (1842) ; Suppl. to Part L, p. 3 



(1840). — De Kay, N. Y. Moll. 75, pi. 36, fig. 348 (1843). — Kusteu (Limnasus), in 



CuEMN. 2d ed. 39, pi. 7, figs. 6, 7. 



Shell tapering, elongated, turretcd, thin and fragile, dnll and 

 dingy horn colored, inelegant ; whorls five or a little more, the two 

 smallest being generally broken off; they are regnlarly and 

 largely convex, not flattened or compressed posteriorly, 

 but the adjacent margins of two whorls curve regularly to 

 the deeply impressed suture ; the last whorl, measured 

 upon the back, constitutes from a little more than one half 

 to about two thirds the whole length of the sliell ; surface 

 coarsely wrinkled by the lines of growth, sometimes mi- 

 nutely reticulated by revolving lines, and sometimes cxhib- 

 iting small, plain facets, irregularly disposed. Aperture 

 generally less than, but never exceeding one half the length of the 

 shell ; sub-oval, rather contracted ; right lip thin, with now and 

 then a sub-marginal thickening, within colored reddish-brown ; pil- 

 lar margin copiously overlaid Avith wliitc enamel, not closely ap- 

 pressed at the umbilical region ; fold of the pillar large and oblique ; 

 umbilicus for the most part closed. Length, nine tenths of an inch ; 

 breadth, four tenths of an inch ; divergence, forty-three to forty-five 

 degrees. 



The animal is of a dusky-greenish color, similar to tliat of the 

 shell, varying like it in intensity, minutely dotted with amber-color. 

 Foot somewhat paler, tongue-shaped, reaching about two thirds the 

 length of the large whorl when in motion, obtusely rounded behind. 

 Ranging from New England, through Pennsylvania and Kansas, 

 to California and Oregon. Very numerous in British America, 

 reaching a high latitude, as shown hy specimens from Hudson's 

 Bay and Fort Resolution. 



The animal attains maturity and dies about the end of June. At 

 this time the young may be seen with the old, about an eighth of 

 an hich in length, and these continue to grow rapidly during the 

 season. But after the early part of July it is rare to find an adult 

 shell containing a living animal. At this time the exterior of the 

 shell is much eroded ; in fact, the animals, as they cluster together, 

 actually devour each other's shells ; the aperture becomes white and 



