200 



sess any crenulations or teeth ; the operculum (of 

 those species which have been found with it), is provid- 

 ed with a lateral tooth on one side. Some species are 

 armed with long spines. Shell thin, semiglobular, or 

 oval; flattened beneath, not umbilicated; opening se- 

 micircular; left margin smooth and sharp. 



Neritina perversa 



pulligera 



: dubia 



zebra 



zigzag 



gagates 



lugubris 



corona 



brevi-spina 



crepidularia 



Neritina Bcetica 



Neritina auriculata 



Domingensis 



fasciata 



lineolata 



semi-conica 



strigilata 



meleagris 



virginea 



fluviatilis 



viridis 



ft 



NERITA. 



NfcRlTA EXUVIA. LitlH. 



Mawes Linnaeus, pi. 30, /*. 1 <§r 7- 



Sowerby's Genera of Shells, No. 15, pi. 4. 

 The true G. Nerita is distinguished from the Neritina 

 by the following characters, independent of its being a 



