160 INTRODUCTION TO CONCHOLOGY. 



also more or less plentiful in Sumatra and other islands of 

 tlie Oriental Archipelago, in India and in South America. 



Shells of the NeritmcB are more stoutly convoluted than 

 those of the NavicellcB, and, as regards the animal inhabitants, 

 there is little difference beyond that which results from dif- 

 ferent locations. The former dwell principally on river-banks, 

 and are found not unfrequently on palms and water-loving 

 plants. 



Few species present any variation of sculpture beyond a 

 slightly plicated or granulated surface, with the exception of 

 such as are coronated with a row of hollow-spouted spines, 

 either short or long. Some are even curiously winged on 

 each side, as the N. dilatata and latissiwa. 



Sea Nerites construct shells of solid growth, and adorn 

 them with extremely vivid colours, which are yet so variable 

 that the closest observation is required to understand their 

 specific relationship. They are also characterized by varia- 

 tions of sculpture which do not pertain to the fresh-water 

 genus. Many are strongly ribbed, others grained, and, in 

 some species, the N. ornata, and well-known Bleeding- tooth, 

 N. peloronta, the flat columellar septum is dentated. 



With regard to the animal inhabitant of the genus Nerita, 

 it differs little from the Neritina. The creatures affect 



