164 NEW UNIONID^, MELANID^, ETC., 



I name this fine species after Dr. Trask, who sent it to me some years since with 

 other interesting species from California. 



Physa Warreniana. pi. 24, fig. 81. 



Testa infiata tenui, diaphana, nitida, albida; spira obtusa ; suturis impressis ; anfractibus quinis, ultimo 

 pergrandi et valde inflato ; apertura late elliptica ; labro acuto, subter marginem fusco et albido-vittata ; 

 columella medio impressa et contorta. 



Shell inflated, thin, somewhat transparent, shining, whitish ; spire obtuse ; sutures 

 impressed ; whorls five, the last one very large and very much inflated ; aperture 

 broadly elliptical ; outer lip acute, brown and white banded under the margin ; 

 columella impressed and twisted in the middle. 



Proo. Acad. Nat. Sci. 1864, p. 115. 



:Eah. — Loup Fork of the Platte River, F. V. Hayden, M. D. ; Milwaukie, Wiscon- 

 sin, H. C. Grosvenor ; Lake near Grand Rapids, Mich., A. 0. Currier. 



My cabinet and cabinet of the Smithsonian Listitution. 

 Diam. -45, Length *70 inch. 



BemarJcs. — About a dozen chiefly immature specimens were brought by Dr. Hayden 

 from the Expedition to the Upper Missouri and Yellow Stone, under Lieut. G. K. 

 Warren, T. E. U. S. A., and to that officer I have great pleasure in dedicating this 

 species. In form and size it is allied to heterostropha, Say, but may be distinguished 

 by being more inflated, being much thinner and of a finer texture, showing the 

 columella through the walls of the shell. The young are very transparent, and 

 when about one third grown are very like virginea, Gould. On the inside the brown 

 bands are strongly marked, while on the outside the white are broader and more 

 prominent. The mature specimens before me have only two bands. The aperture 

 is about three-fourteenths the length of the shell. 



Phtsa Altonensis. PL 24, fig. 82. 



Testa elliptica, subcrassa, laeviuscula, pallido-castanea ; spira breviusoula ; suturis impressis; anfractibus 

 quinis, ultimo grandi ; apertura ovata, subgrandi ; labro acuto, subter marginem incrassato et crocato- 

 vittata ; columella inferne magna plica induta. 



Shell elliptical, rather thick, rather smooth, pale chestnut color ; spire rather short ; 

 sutures impressed ; whorls five, the last one large ; aperture ovate, rather large ; 

 outer lip acute, thickened under the margin and safiron banded ; columella furnished 

 below with a large fold. 



Proc. Acad. Nat. Sci. 1864, p. 114. 



nab. — Alton, Illinois, Mr. Henry Lea. 



My cabinet. 

 Diam. '35, ,_ Length '55 inches. 



