244 



MAl^FAL OF THE MOLLUSCA. 



Ceritli. radulura and granulatum of the West African rivers 

 approacL. very near tlie fossil potamides, but they have numerous 

 varices. 



Lampania, Gray (batillaria, Cantor). Oerith. zonale. PL 

 VIII., Fig. 23. 



Shell without varices, canal straight. Chusan. 



The fossil potamides decussatus, Brug., of the Paris baLin, 

 resembles this section, and retains its spiral red bands. 



Nerinjea, Defrance. 



Etymology, nereis, a sea-njnnph. 



Example, N. trachea. Pig. 98. 



Shell elongated ; many-whorled, nearly cylindrical ; 

 aperture channeled in front ; interior with continuous 

 ridges on the columella and whorls. 



Fossil, 150 species. Inf. oolite — IJ. chalk. Britain, 

 Prance, Germany, Spain, and Portugal. They are 

 most abundant, and attain the largest size to the 

 south ; and usually occur in calcareous strata, asso- 

 ciated with shallow- water shells. (Sharpe.) 



Suh-ge.7i,era. 1. Nerinoea. Polds simple: 2 — 3 on 

 the columella ; 1 — 2 on the outer wall ; columella solid, 

 or perforated. Above 50 species. 



2. iVenwe^/a (Sharpe), columella solid; folds simple; 

 columellar, — 1 ; outer wall, 1. 



3. Trochalia (Sharpe), columella perforated, with 

 one fold ; outer wall simple, or thickened, or with one 

 fold ; folds simple. 



4. Ptygmatis (Sharpe), columella solid or perforated, 

 usually with 3 folds ; outer wall with 1 — 3 folds, some 

 of them complicated in form. 



Kg. 98.* 



? P ASTIGIELLA, Eecve. 



Type, P. carinata, Eeeve. 



Shell like turritella; aperture with a short canal in front 

 (Cuming Museum, and British Museum). 



Fossil, Eocene. Paris [Qerithium rugosum. Lam.). 



Aporehais, Aldrovandus. 



Etymology, aporrhais (Aristotle), " spout-shell," from aporrheo, 

 to flow away. 



* Fig. 98. JVenruea trachea, Desl., partly ground down to show the form of the 

 interior. Bath oolite, Eanville. Communicated by John Morris, Esq. 



