GASTEEOPODA. 



Shell oval, elongated, ventricose, thick ; 

 w^horls rounded or rendered angular by the 

 upper portion being channelled ; last whorl 

 much deyeloped. Ornamentation usually of 

 large longitudinal ribs, crossed by numerous 

 striae ; aperture large in the young state, 

 slightly notched in front ; columella rounded ; 

 umbilical groove deep, narrow, but well de- 

 fined. 



Fossil, 8 species. Inferior Oolite — Kelloway 



' -^ ^ -' Fig. 12 Farpurtna 



Eock. England, h ranee, (iermany. Beiiona. 



ToRELLiA (LoTen), JeflEi^eys, 1867. 



Dedicated to Dr. Otto Torell, of Norway. 



Type, T. yestita, Jefireys. Shetland and Norway. 



Animal with the produced lips and lingual dentition of 

 Cajndus. 



Shell globose, covered with a velvety epidermis ; spire very 

 short ; apex depressed ; aperture roundish ; pillar with a blunt 

 tubercle at its base ; groove internal, scarcely perceptible ; 

 operculum like that of Trichotrojois. 



[Family Neritopsid^.] 



Genera : — ^Neritopsis and Nauica with Naticella as a sub- 

 genus (see p. 261). 



[Eamlly Pyeamedellid^.*] 



The following genera and sub -genera are additional : — 



Pyramedeela. Sub-genus Chrysallida, P. Carpenter, 1857. 



Shell pupiform ; peristone continuous ; edge of lip thin ; 

 columella-plait distinct, though hidden; operculum in the 

 typical species radiately corrugated. 



Distribution, 25 species. E. and W. Indies, Japan, Mazatlan. 



Odostomia. Some of the Mazatlan species have the peri- 

 stone continuous. 



Sub-genera : — Auriculina, Gray. 



Shell having the general aspect of Odostomia, but presenting 

 no vestige of a plait. Mazatlan, 3 species. 



Fossil, 4 species. Tertiary. United States. 



Parthenia, Lowe [Ehalia, Adams). Surface sculptiu'ed ; 

 columella plaited. 



Dietrilution, 10 species. Mazatlan, Japan. 



* See p. 238. 



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