AMNICOLA. 293 



Shell thin in texture, conical, rather robust, composed of four 

 and a half convex whorls, separated by a well-marked suture ; spire 

 obtuse, rather longer than the aperture ; umbilicus narrow ; 

 aperture Ovate-orbicular, forming an angle posteriorly ; a '° ' 

 small portion of the labium continent with the body whorl 

 posteriorly. Color pale ochraceous, translucent. 



Inhabits Lake Champlain {Adams). ^'da!'' 



Intermediate between lustrica and porata. It is not as 

 short and transverse as the former, which, moreover, is widely um- 

 bilicate, and has the aperture regularly rounded posteriorly. Ac- 

 cording to the description of Professor Adams, the labium some- 

 times scarcely touches the body of the shell. The spire is compar- 

 atively longer than in porata, the outline less transverse, and the 

 aperture not orbicular (^Haldemari). 



Hartford ( Linslei/} . 



Amnicola limosa. 



Fig. 157. 



Shell small, sub-globose, thin, smooth ; whorls four, very convex, suture deep; 

 aperture nearly circular ; inner lip barely touching the preceding whorl ; umbili- 

 cus large. 



Paludina limom. Say, Journ. Ac. Nit. Sc. Phila. i. 125 (1817); Nich. Encyc. 3d ed. 



(1819) ; Binney's ed. 61. — De K.\v, N. Y. Moll. 88. 

 Paludina porata, Adams, in Thompson's Hist, of Vt. 152 (1812) (teste Hald.). — Phi- 



LiPPi, Z. fiir Mai. ii. 77 (1845). 

 Amnico/a porata, Gould, Inv. of Mass. 1st ed. 229, fig. 157 (1841). 

 Amnicola limosa, Haldeman, Mon. 10, pi. 1, figs. 5, 6 (1844''). — Anonymous, Can. Nat. 



ii. 214, fig. (1857). — W. G. Binney, L. and Fr. W. Shells, iii. 84, fig. 166 (1865). 



Shell minute, conic-globose, thin, translucent, smooth, or with 

 most delicate lines of growth ; varying from a bronze-green 



Fiff. 559. 



to a light olive-green color, but usually invested with mud ; 

 whorls four or less, very convex, and flattened near the 

 suture, so as to present a conspicuous shoulder ; the last a. umo- 

 whorl rather more than two thirds the length of the shell, 

 and as broad as long ; suture deeply impressed, almost chan- 

 nelled ; aperture nearly circular, both lips being about equally 

 curved, and uniting posteriorly at a broad angle ; lips sharp, in 

 some instances a little everted ; inner lip at maturity, barely touch- 

 ing the preceding whorl just before it joins the outer lip, leaving a 

 very large, deep umbilicus. Length, three twentieths of an inch; 

 breadth, five tenths of an inch ; divergence, sixty-eight degrees. 



