loi UNIVALVES. — NERITA. 



-HERIT A.— Nerite or Hoof-Shell. 



Division I. — Shell umbilicated. 

 Family l.^-With the umbilicus rather large, nearly pervious. 

 Vitellus — Clouded-yellow. Rugosa — Wrinkled. 



Punctata — Punctured. Vittata — Ribbon. 



Cruentata — Red- spotted. *Pallidula — Pallid. 



Family 2. — With the umbilicus bifid. 

 *Canrena — Tabby-cat. Sulcata — Grooved. 



Ca.r\ce\lat3i-~-Latticed. Spadicea — Chesnut. 



Rufa — Reddish. 



Family 3. — JVith the umbilicus nearly closed by a callus, or by 



the inner lip, 

 *GIaucina — Livid. Albumen — Liver-coloured. 



Orientalis — Eastern. Mammilla — Breast. 



Maroccana — Wave-striped. Papilla — Nipple. 



Arachnoidea — Spider' s-web. Melanostoma — Brown-pillar. 



Ambigua — Ambiguous. 



Family 4. — With the umbilicus toothed. 

 Fulminea — Ziczag. 



Division II. — Shell imperforate and toothless. 



Family 1. — Spinous. 



Corona — Crowned. 



Family 2. — Without spines. 

 Radula — Rough-ribbed. *Littoralis — Strand. 



Magdalena — Magdalen. *Lacustri3 — Lake. 



Cornea — Horny. *Dubia — Black-mark. 



*Fliiviatilis — River. *Marginata — Margined. 



Division III. — Shell imperforate and toothed. 

 Family 1. — With the inner lip toothed. 

 PuUigera — Reddish, Aculeata — Spinous. 



