NAVICELLA. 159 



of the disc and the viscera, and occupying the spiral 

 chambers of the shell ; the other is of a stouter substance, 

 and appears to radiate at a right angle with the former. 



Navicell(R are singularly restricted in their geographical 

 distribution. They are unknown to Europe and the western 

 hemisphere, but abound in the streams of the Philippine and 

 Feejee islands; they are found also in New Guinea, IN'ew 

 Ireland, New Holland, and in Mauritius and the neigh- 

 bouring isles, where they serve as food to the poorer 

 natives. The largest species is prettily variegated with 

 yellow upon a dark olive-black ground. The N. lineata 

 and Recluzii are delicate both in shape and colour; they 

 are compressly oblong, and resemble a fragile boat, of which 

 the septum forms the poop. 



NeritincBj or Fresh-water Nerites, have scarcely any 

 geographical restriction, except in the frigid and cold tem- 

 perate zones. The genus is represented by a humble but 

 very prettily painted species on our own coast, and is 

 ])lentiful in the West Indies, as also frequent throughout 

 the continent of North, South, and Central America. 

 Magnificent specimens were collected by Mr. Cuming in 

 the Philippines, among which the N. laliosa, a fine stout 

 richly-painted shell, is, perhaps, the largest. NeritcB are 



