EULIMID.5;, 2()5 



lip ver}- slightly notched near the uj^per end ; surface of shell 

 smooth. Paloeozoic, United States. 



BidimeUa, of Hall (not Pfeiffer) ; ^^/z/nor/^/m, Whitfield, 1882, 

 and Poly phemop sis. Portlock (in part), are s3'non3^ms. 



Genus FUSISPIRA, Hall, 1872. 

 This Silurian group, wliith I have placed in Buccinida?, may 

 possibh- belong here. 

 F. VENTRicosA, Hall (Struct, and Syst. Conch., ii, 141, t. 51, f. 50). 



Genus CHEMNITZIA, d'Orb., 1850. 



Shell comparatively large, elongate conical ; spire manj^- 

 whorled, the last rather large, somewhat produced below ; aper- 

 ture ovate, somewhat effuse at base, peristome not continuous, 

 outer lip sharp, sinuous at or above the middle, columella smooth, 

 imperforate ; surface longitudinally' striate or costate, sometimes 

 decussated, rarely nodular. Secondary and Tertiary. C. con- 

 DENSATA, Desh. (Struct, and Syst. Conch., ii, t. 68, f. 96). 



The recent shells known as Chemyntzia,n.\\({ which were origi- 

 nall}' included by d'Orbignj' in his diagnosis of 1839, are referred 

 to Turbonilla, Risso ; they are smaller, ribbed, and do not possess 

 the broad posterior lip-sinus of the fossil group. 



Section Chemnitzta (restricted). 



Shell lengthened, with cross ribs ; mouth oval, rounded or 

 angular in front ; spire straight or slightl}' curved, somewhat 

 callous ; outer lip sharp. 



Section Rhabdoconcha, Gemellaro, 18T8. 



Whorls striate or ribbed longitudinall}', sometimes punctate 

 or tuberculate. 



Section Pseudomelania, Pictet et Campicbe, 1862. 



Shell elongated, thick; whorls smooth, with fine curved growth- 

 lines ; mouth rounded or angular in front; spire straight or 

 slightly curved. 



Section Oonia, Gemellaro, 18T8. 



Shell egg-shaped, smooth, with growth-lines ; last whorl large ; 

 mouth oval, rounded in front; spire slightl}' curved. 



Section Microschiza, Gemellaro, 1878. 



Shell usnall}' with cross ribs; narrowly peifurate ; whorls 



