120 MOLLUSCA. 
Puysa VIRGINEA (Gould). 
Testa elongato-ovata, tenuis, fragilis, lucida, nitida, alba: spira acuta, 
anfractibus quinque convexis, postice subangulatis: apertura elongata, 
obovata, posticé acuta ; columella leviter plicata. 
Physa virginea, Gouin; Proceed. Boston Soc. Nat. Hist., ii. 215. 
June 1847. Expedition Shells, 43. 
SHELL slender and delicate, thin and shining, of a milk-white or 
porcelain-white colour: spire about one-third the length of shell, 
sharply pointed, of five or more moderately convex whorls, the last of 
which has a faintly angular appearance near the suture. Aperture 
narrow and elongated, two-thirds the length of shell, acute behind. 
Columella short, delicate, slightly sinuate, folded. 
Length three-fifths of an inch; diameter one-third of an inch. 
Inhabits the Sacramento River, California. Lieutenant Budd. 
A very well-marked species, of a porcelain-like structure and co- 
lour, which appears not to be the consequence merely of blanching. 
It is less slender than P. hypnorum, and more like P. gyrina, Say, or 
P. rivalis, in form, but is a far more delicate shell, and one of the most 
elongated species. 
Figures 138, 138 a, two views of the shell. 
Puysa RivaLis (Potier and Micu.), Galerie, 226, pl. 22, figs. 21, 
22. D’Orsicny; Amer. Merid. 341. Gray; Spicil. Zool. 1828. 
Anima much elongated, of an indigo-blue colour, pale greenish at 
the edges; head and tentacles small; mantle largely developed, and 
with numerous short fimbrie, radiately striped with greenish and 
indigo. 
