CHIEFLY OF THE UNITED STATES. 167 



Physa tenuissima. pi. 24, fig. 86. 



Testa subfusiformi, tenuissima, fragilissima, diaphana, nitida, albida ; spira producta ; suturis vix impres- 

 sis ; anfractibus quaternis couvesiusculis, ultimo pergrandi et subcompresso ; apertura grandi, 

 elongato-ovata ; labro acuto ; subexpanso ; columella tenui, vix contorta. 



Shell subfusiforra, exceedingly thin, very fragile, transparent, shining, whitish ; 

 spire produced; sutures scarcely impressed; whorls four, slightly convex, the last 

 one very large and somewhat compressed ; aperture large, elongately ovate ; outer 

 lip slightly expanded ; columella thin and slightly twisted. 

 Proe. Acad. Nat. Sei., 1864, p. 114. 



Hah. — Alexandria, Louisiana, J. Hale, M. D. 



My cabinet. 

 Diam. -25, Length -55 inch. 



Remarks. — A single specimen only of this graceful and very delicate species was 

 received from Dr. Hale, and it was so much broken that I had much difficulty in 

 making a correct drawing of it. The form is very unusual with the Physa, having 

 much the appearance of a reversed Lymnaia or Succinea. The aperture is not quite 

 two-thirds the length of the shell. 



'b"- 



Physa Saffordii. PI. 24, fig. 87. 



Testa subfusiformi, subcompressa, opaca, albida, polita, crassiuscula ; spira parum producta, acuminata ; 

 suturis impressis; anfractibus quinis, ultimo grandi ; apertura ovata, grandiuscula ; labro parum ex- 

 panso, subter marginem incrassato et dilute fusoo ; columella parum incrassata et vix plicata. 



Shell subfusiform, slightly compressed, opake white,- polished, somewhat thick ; 



spire somewhat produced, pointed ; sutures impressed ; whorls five, the last one 



large ; aperture ovate, somewhat large ; outer lip somewhat expanded, thickened 



and pale brown within the margin ; columella slightly thickened and scarcely folded. 



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



Hah. — Lebanon, Wilson Co., Tenn., Mr. J. M. Safibrd ; Verdigris River, Kansas, 

 F. Hawn, and Nashville, Prof. Troost. 



My cabinet and cabinets of Mr. Safibrd and Smithsonian Institution. 

 Diam. "25, Length •48 inch. 



Remarlcs. — This graceful and symmetrical species was sent to me many years since, 

 and I have great pleasure in now naming it after Mr. SafFord, who very kindly sent 

 me many interesting fresh water shells from Tennessee. The substance of the shell 

 is rather thick and opake white, and being porcelainic reminds one of an immature 

 white Gyproia or Marginella. Two of the specimens have but a single white band 

 immediately under the margin of the outer lip. One has two and the fourth specimen 

 has four bands. In outline and size they are the same. In this the species is allied 



