LIMN^A. 479 



the spire, and with one whorl more than L. desidiosa. The habits 

 of tlie two last are similar, but the animal of desidiosa is a much 

 lighter green, and has not the remarkable white dots between the 

 tentacula. 



The cliaractcrs of the aperture and spire seem to be constant ; 

 that is, the aperture is always large and broadly rounded behind ; 

 and the spire is tapering, the two whorls at the tip seeming some- 

 what as if superadded ; so that if a line should pass down one side 

 so as to touch all the whorls, this line would be concave. The only 

 variations I have noticed are, that the suture is sometimes shal- 

 low, and the shoulder nearly wanting, so as to render the spire 

 more regularly tapering, Mr. Say's description is not definite, and 

 his figure is much shorter than the dimensions he ascribes to it. 

 He gives its length seven tenths of an inch, Avhile it rarely exceeds 

 half an inch. 



Limnsea catascopium. 



Shell ovate, strong, chestnut brown ; whorls four, wrinkled, convex, the last 

 large ; suture deep ; aperture sub-oval, half the length of the shell. 



Limncen catascopium, Say, Nich. Ency. pi. 11, fig. 3 (1817, 1818, 1819) ; Am. Conch, vi. 

 pi. .55, fig. 2 (1834) ; ed. Binney, 4.5, 211, pi. 70, fig. 3 ; pi. 55, fig. 2. — Halde- 

 MAV, Men. 6, pi. i. (1841). — Gould, Iiiv. of Mass. 223 (1841). — De Kay, N. Y. 

 Moll. 67, pi. 6, fig. 80 (1843). —Mrs. Gray. Fig. Moll. An. pi. 310, fig. 7. — Ktis- 

 TER, in Chemx. 2d ed. {Limnceus), 46, pi. 8, figs. 15-21. — Potiez et Michaud, 

 Gal. des Moll. i. 216, pi. 21, figs. 3, 4. — Anon. Can. Nat. ii. 201, fig. (1857). —W. 

 G. BiNNEY, Smith. Inst. L. and Fr. W. Shells, ii. 53, figs. 80-84 (1865). 



LimncBa cornea, Valenciennes, Hiimb. & Bonpl. Rec. 18.33, ii. 251. 



LimiKBa pinijnis. Say, J. A. N. So. v. 123 (18:25) ; ed. Binney, 114 (not of Dohrn, Pr. 

 Zool. See. 1858, 134). 



Limncea Vii(^iniana, Lamarck, An. sans Vert. vi. 160. — Deshayes, in Lam. 8, 411 ; 2d 

 ed. iii. 416 ; Encyc. Mcth. Vers, ii. 362 (18.30). — Delessert, Rec. des Coq. xx.k. 4 

 (1831). 



Limmca s ricata, Ziegler teste Haldeman. 



Il'lix caiascopius, Eaton, Zool. Text Book, 195 (1826). 



Shell rather large, oblong-ovate, ventricose, thick and strong; 

 epidermis chestnut or brownish horn color ; whorls four 

 or a little more, forming a short, pointed spire, delicately ^'^^ '^o. 

 but rather regularly wrinkled by the lines of growth, and 

 these are rendered somewhat corrugated by obsolete re- 

 volving lines ; last whorl constituting nearly the whole 

 shell, very much distended ; suture deeply impressed ; 

 spire very short, acute at apex ; aperture rather more 

 than half the length of the shell, sub-oval, very little nar- 

 rowed behind, not dilated ; right lip simple, thick, and regularly 



