484 limnjiidj:. 



Physa hdrrostropha, Sat, Journ. Acad. Nat. Sc. ii. 172 (1821) ; Binney's crl. 68. — Hal- 

 DEMAN, Mon. 23, pi. 2, figs. 1-9 (1843). — Gould, Inv. 211, fig. 141 (1841).— 

 Adams, Shells of Vt. l.')4 (1842). — Deshaye.s, in Lam. An. sans Vert. viii. 402; 

 2d 0(1. iii. 412. -De Kay, N. Y. Moll. 76, pi. 5, fig. 82 (1843). — Chemnitz, 2d 

 ed. 7, pi. 1, figs. 7, 8. — Mrs. Gray, Fig. Moll. An. pi. 310, fig. 9. — Potiez ct 

 MiCHAUD, Gal. des Moll. i. 224, pi. 22, figs. 15, 16. — Anony. Canad. Nat. ii. 209, 

 fig. (1857). — W. G. BiNNEY, Smith. Inst. L. and Fr. W. Shells, ii. 84, figs. 144, 

 145 (1865). 



P/ii/sa foiitaud, Haldeman, Mon. part 2, p. 3 of cover (1841). 



Phi/m ci/lindrica, Newcomb, in De Kay, N. Y. Moll. 77, pi. 5, fig. 82 (1843). 



P/ii/m aurea, Lea, Trans. Am. Fhil. Soc. vi. 18, pi. 23, fig. 106; Obs. ii. 18 (1839).— 

 De Kay, N. Y. Moll. 80, pi. 5, fig. 89 (1843). 



Physa plicata, De Kay, N. Y. Moll. 78, pi. 5, fig. 85 (1843). 



Physa oscuians, Haldeman, Mon. part, figs. 11, 12. 



Physa striata, Menke, Syn. Me'th, 2d ed. 132 (1830), tPste Haldeman. 



Physa suharata, Menke, Syn. Me'th. 2d ed. 132 (1830), teste Haldeman. 



Physa Charpmtieri, Kuster, in Chemn. 2d ed. 23, pi, 4, figs. 4-6. 



IViysa PhiUppi, Kuster, in Chemn. 2d ed. 19, pi. 3, figs. 3-6. 



Physa injlata, Lea, Proc. Am. Phil. Soc. ii. 32 ; Trans, ix. 7 ; Obs. iv. 7. 



Plellx hcterostrophus, Eaton, Zool. Text Book, 195 (1826). 



Bulla crassula, Dillwyn, Conch, t. 1,487, No. 36 =fontinalis, Chemnitz, Conch, ix. 

 33, pi. 103, figs. 879, 880, var. 3. — Gmelin, Syst. 3407. — Schroter, Einl. t. 1, 

 261, Helix, No. 84. 



CWhIea neritoides, Lister, Conch, pi. 135, fig. 34. 



" Shell sinistral, sub-ovate ; color pale yellow, chestnut, or black- 

 ish ; whorls four, the first large, the others very small, terminating 

 rather abruptly in an acute apex ; aperture large, somewhat 

 oval, three fourths the length of the shell, or rather more ; 

 within of a pearly lustre, often blackish ; lip a little thick- 

 ened on the inside, and tinged with dull red." (Say, in 

 ^^ Nich. Encyc") Ordinary length, about half an inch ; 

 breadth, one fourth of an inch ; divergence, sixty-eight de- 

 grees. j\Iy largest specimen is seven tenths of an inch by 

 two fifths of an inch. 

 When the shell is fresh and perfectly clean it is always of a light 

 greenish-yellow, and becomes a little more dusky with age. Tlic 

 surface, under the magnifier, appears beautifully checkered with 

 minute, revolving, and longitudinal lines, which are also a little 

 waved. Sometimes there are one or more whitisli, opaque frauds, 

 as if scratched by the mantle of the animal. The thickening of the 

 lip is found only in old s])ecimcns, and in these also there is a broad 

 layer of pearly enamel reflected over the columella, which has also a 

 very prominent fold. 



The animal is olivaceous, surface very smooth and silky ; the foot 

 is kite-shaped, longer than the shell, terminating in an acute point ; 

 expansions each side of the mouth acutely angled ; tentacula oli- 



