492 limn^idj:. 



more than three, as seen on both sides, forming on the right side a 

 large and deep concavity, bounded by a sharp, raised line 

 Fig. 74a. ^^. yr^j.^j^jj^ and on the left side a still deeper, inversely 

 conic cavity, bounded by a similar carina, but of smaller 

 circuit ; surface rather smooth, with faint, irregular, 

 lines of growth, most distinct on the right side ; aper- 

 ture ovate, right side broadest, and on the general plane 

 of that side of the shell ; left margin strongly modified 

 p. bicarinatus. ^^J ^^^^ Carina, and extending far beyond the plane of 

 the preceding whorl ; lip slightly expanded, white; in- 

 terior brownish, with white lines in the grooves answering to the 

 carina. Longest diameter, half an inch ; shortest diameter, three 

 tenths of an inch. 



Animal light russet color, beautifully dotted with amber ; foot 

 tongue-shaped, nearly as long as the diameter of the shell. The 

 strong angle of the aperture fully displays the respiratory opening, 

 which has a jagged flap, over which lies an acute groove ; move- 

 ments sluggish. 



Inhabits still waters, not so generally pools as the margins of 

 large ponds. Not very common. 



This s])ecies is smaller than either of the preceding, and is at 

 once distinguished from them by the very obvious angularity of the 

 whorls on both side«, and Ijy the very deep, conical cavity of the 

 left side. Sometimes a few faint revolving lines may be found on 

 the surface. The tentacula of the animal are usually very long, but 

 sometimes one or both of them seem to have been broken. 



[The species ranges from the British possessions to Kansas and 

 Georgia. 



Planorbis campantilatus. 



Fig. 1.33. 



Shell with the last whorl distorted, concave on both sides ; whorls four, strongly 

 carinate on the left, and sub-carinate on the right side ; throat camijanulate ; ap- 

 erture turned to the left. 



Planorhis campannlatiis, Say, Journ. Acad. Nat. Sc. ii. 166 (1821) ; Binney's ed. 64.— 

 Haldeman, Mon. 9, pi. 1, fi^s. 7-11 (1844). — Gould, Tnv. 204. fig. 133 (1841).— 

 Adams, Shells of Vt. 1.5.5 (1841). — De Kay, N. Y. Moll. 61, pi. 5, figs. 99* a, b 

 (1843). — KtJSTER, in Chemn. 2d ed. .52, pi. 9, figs. 7-10. — Anox. Can. Nat. ii. 

 204, fig. (1857). — W. G. Binney, Smith. Inst. L. and Fr. W. Shells, ii. 109, fig. 

 184 (186.5). 



Planorhis bellus. Lea, Tr. Am. Phil. Soc. ix. 6 (1844) ; Froc. ii. 32 (1841). 



Planorbis bicarinatus, Sowerby, Gen. pi. 4. 



