244 NEW YORK STATE MUSEUM 



This genus is well represented among the recent shells in this 

 vicinity. They may be found in all the streams tributary to the 

 Niagara. 



Limnaea columella Say 1817 (Fig. 171). L. columella 

 Say (1817. Acad. nat. sci. Phil. Jour. 1:14) 



This is a very thin, fragile shell having four whorls, 

 rapidly diminishing, separated by a distinct but not 

 deeply impressed suture; aperture large, more than one 

 half the length of the shell; lip simple, and surface 

 pig 171 Lim- longitudinally wrinkled by growth lines. 



naea columella T 1 . . /^ ., • 1 j i • L 



Locality. Goat island gravel pits. 

 Only one specimen of this species was found, leading me to be- 

 lieve that it was an uncommon shell in early post-Pliocene times, as 

 it is at the present time, Lime lake being the only locality 

 in this vicinity where the recent shell occurs. 



Limnaea desidiosa Say 1821 (Fig. 172). L. de- 

 si d i o s a Say (1821. Acad. nat. sci. Phil. Jour. 2:169) 

 Shell oblong and subconic, with five very convex 

 whorls; suture deeply impressed; last whorl slightly 

 swollen; slight growth lines visible with a lens. naea' desidiosa 



Localities. Goat island, Whirlpool and Foster's flats. 

 This is the most common Limnaea found in these deposits. 

 Limnaea catascopium Say 1817 (Fig. 173). L. catascop- 

 i u m Say (1817-19. Nick, cue. Am. cd. p. 11, fig. 3. 1834. 

 Am. conch, v 6. pi. v, fig. 2; 1841. Haldeman. Monograph 

 6, pi. 1) 



Shell thin, sculptured spirally by delicate lines, giving it 



naeacata-'a very beautiful appearance under the lens; growth lines 



=copium j ieaV y at t } ie su ture, making slight plications; whorls four 



or five, decreasing to an acute apex; aperture about three quarters 



the length of the shell; lip simple, folding back on the columellar 



side and leaving a narrow umbilicus. 



Localities. Goat island, Whirlpool and Foster's flats. 



Genus physa Draparnaud 



The animal of Physa is triangular in general shape; tentacles 

 slender and setaceous; mantle covers part of the shell, the margin 

 folding over the body whorl in a fringe. The shell is sinistral, thin, 

 with an acute spire; body whorl large, inflated and the aperture 

 large and oval; lip simple. 



