LIMN^A. 471 



long, apex attenuated, recurved ; laterals broad, blunt, apex re- 

 curved, denticulated. 



This genus is found over almost the whole world, but prefers the 

 more temperate portions of it. In North America, likewise, it is 

 found in greater abundance and perfection in the lake region of the 

 United States, and still more so in the British possessions. In the 

 States bordering on the Gulf, and in Mexico, it is hardly represented. 



Linmaea columella. 



Fig. 144. 



Shell ovate, fragile, transparent, pale-greeu ; whorls four, the three upper ones 

 minute, lines of growth distinct, undulated by revolving lines; aperture ample; 

 umbilicus minute. 



Limmva columella, Say, Journ. Acad. Nat. Sc. riiila. i. 14 (1817); ii. 167 (1821); Nidi. 



Eiu-yc. 3d ed. (1819); Binney's cd. 60, .56. — Haldeman, Mon. 38, pi. 12 (1842). 



— Gould, Inv. of Mass. 215, figs. 144, 216, fig. 145 (1841).— De Kay, N. Y. Moll. 



72, pi. 4, fig. 75 (184-3). — Potiez ct Miciiaud, Gal. i. 216, pi. 22, figs. 5, 6. — 



Anox. Can. Natural, ii. 197, fig. (1857). — W. G. Binney, Smith. Inst. L. and Fr. 



W. Shells, ii. 32, figs. 38-44 (1865). 

 Limneus columella, Kuster, in Ciiemn. 2d cd. 44, pi. 8, figs. 3-5. 

 Limncea chali/hea, Gould, Am. Journ. Sc. [i], xxxviii. 196 (1840) ; Otia, 180. 

 Liinmea macrostoma, Say, Journ. Acad. Nat. Sc. ii. 170 ( 1821 ) ; Binney's ed. 67. — Gould, 



Inv. 217, fig. 148 (1841 ).— Anon. Can. Nat. ii. 198, fig. (1857). 

 Limneus macrostuiiius, Kijster, in Chemn. 2d cd. 43, pi. 8, figs. 1, 2. 

 Llmmen ticuminata, Adams, Am. Journ. Sc. [i], xxxix. 374 (1840). 

 Limnica navicula, Valenciennes, Rcc d'Obs. ii. 251 (1833). 

 Limnmi strlcjosa. Lea, Proc Am. riiil. Soc. ii. 33 (1841); Trans, ix. 12 (1844); Obs. 



iv. 12. 

 Liviiuva coarclata, Lea, Proc. Am. Phil. Soc. ii. 33 (1841) ; Trans, ix. 11 (1844) ; Obs. 



iv. 11. 

 Limnmi casta, Lea, Proc. Am. Phil. Soc. ii. 33 (1841) ; Trans, ix. 11 (1844) ; Obs. iv. 11. 

 Limncea culumellaris, Adams, Sillim. Journ. [i], xxxvi. 392, absq. dcscr. 

 Linincea succini/ormis, Adams, MS. teste Haldeman. 



Shell ovate, ventricose, extremely thin and fragile, 

 transparent, of a pale greenish or yellowish color, the 

 apex acutely pointed ; whorls four, of which the last is 

 much inflated, and composes nearly the whole shell ; the 

 upper ones are very small, forming an acute apex ; sur- 

 face with conspicuous and nearly regular lines of growth, 

 minutely waved by revolving lines, some of which are 2.. co^^w^/a. 

 distinctly elevated ; suture slightly impressed ; aperture 

 large, four fifths the length of the shell, generally somewhat di- 

 lated ; lip very sharp, ending with a small curve behind ; on the 



