NERITA. 



TESTA solida, crassiuscula, semi-glob osa, sub tiis 

 planiuscula, spira brevi, umbilico nullo. Aper- 

 tura semi-orbicularis, Integra, labio interno 



crenulato. Operculum ( testaceum ) appendicut 

 latum. 



While tlie advantages resulting to the scientific concho- 

 iogical students from the improved classification of modern 

 authors is every day more and more highly appreciated^ we 

 ar^ sure we shall not incur the displeasure of our readers 

 for presenting to them the Genus Nerita^ separated from 

 Neritina and Natica. Notwithstanding there are those who 

 still think that Nerita and Neritina form together but one 

 natural Genus, because, forsooth, they do not find any 

 material diversity in the general structure of their ani^- 

 mals, and Who tell us that difference in habit, or the 

 circumstance of their dwelling in fresh water or in the 

 Sea, or on dry land, are not to be taken into consideration 

 and do not constitute real differences, because they know 

 that certain species of Mytili and Lamarckian Arcaceas 

 are found inhabiting fresh water; we, for ourselves^ 

 cannot avoid again expressing oin* conviction, that where, 

 essential differences in the shell only, independantly of 

 the animal, do exist, in combination with diversity of 

 economy and habit, and where many species manifest the 

 same peculiarities, there is good and sufficient reason for 

 regarding them as distinct genera; wherefore, we do not 

 hesitate to avow our conviction that Nerita is properly 

 separated from Neritina. 



Shell semiglobular or obovate, solid, generally thick^ 

 in which peculiarity it differs from Neritina, as well as in 



