,178 NEW UNIONID^, MELANIDiE, ETC., 



Diam. -30, Length -66 inch. 



Remarks. — A single specimen only was sent to me some years since by Dr. Wilson, 

 after whom I name it. It is a slender, symmetrical, graceful species, and is one of a 

 group which may embrace Wardiana, (nobis,) Concordialis, Gould, Haydeni, N. G. 

 Binny, vermeta, Say, and retusa, (nobis). It has one more whorl than either of these 

 species, and is quite as oblique as retusa. The color is richer than in any of them. 

 The aperture is about seven-twelfths the length of the shell. 



SUCCINEA PELLUCIDA. PI. 24, fig. 106. 



Testa elongato-obliqua, Isevi, aitida, pelluoida, alba, perteaui ; spira exserta, acuminata; suturis impressis; 

 anfractibus quaternis, vix convexis ; apertura grandiuscula, ovata ; labro subexpanso ; columella 

 tenui, incurva et contorta. 



Shell obliquely elongate, smooth, shining, transparent, white, very thin ; spire ex- 

 serted, pointed ; sutures impressed ; whorls four, slightly convex ; aperture somewhat 

 large, ovate ; outer lip somewhat expanded ; columella thin, incurved and twisted. 

 Proc. Acad. Nat. Sci., 1864, p. 110. 



Hah. — United Slates. 



My cabinet. 

 Diam. -30, Length -55 inch. 



Remarlcs. — About a dozen specimens are before me. The exact habitat I am not 

 acquainted with, but am inclined to believe it to be in some part of the Western 

 States or Territories. It is one of the most fragile of the genus, and has almost the 

 clearness of glass. The columella is plainly visible to the top from the outside. The 

 lines of increement are very feeble. In some of the specimens a portion of a fifth 

 whorl may be seen. Under the microscope very minute revolving strias are visible. 

 The fold on the columella is exceedingly thin and delicate. The aperture is about 

 seven-tenths the length of the shell. It is greatly to be regretted that the living soft 

 parts of the species should not be observed. 



SUCCINEA FORSHEYI. PI. 24, fig. 107. 



Testa elongato-obliqua, Isevi, nitida, diaphana, subaurea, pertenui ; spira exserta, acuminata ; suturis im- 

 pressis; anfractibus ternis, convexiusculis ; apertura grandi, latoovata ; labro subexpanso; columella 

 tenui, incurva et contorta. 



Shell obliquely elongate, smooth, polished, semi-transparent, pale golden color, very 

 thin; spire exserted, pointed; sutures impressed; whorls three, a little convex; 

 aperture large, wide ovate; outer lip somewhat expanded; columella thin, incurved 

 and twisted. 



Proc. Acad. Nat. Sci., 1864, p. 109. 



