471 



Nerita lacuftris. Gmd. Syji. p. 367 7 ?—G:uIt. t. 4. M. 11. 

 Turt. Lin. iv. p. 550. 



N. \^'ith a fub-pellucid, fub-oval fliell, elegantly fpot- 

 ted, flreaked, or mottled with white and purpli(h-brown, 

 pink, or pale-brown; with all the intermediate (hades, 

 for fcarce two are found alike, either in colour or mark- 

 ings ; fome have one or two fpiral bands: volutions 

 three, the firft extremely large, the others very fmall, 

 but well defined, and placed lateral ; apex minutely 

 fmall, a little produced : is frequently covered with a 

 brown or greenifh epidermis when alive, which remo- 

 ved, the (hell is gloffy and fmooth, except examined by 

 a lens, when it is found to be finely wrinkled: aperture 

 iunated; outer lip thin; pillar lip broad, flat, and white; 

 mouth clofed by a teftaceous operculum, of an orange -yel- 

 low. Length three eighths of an inch; breadth two-eighths. 



This fpecies is found plentiful in many of our flow 

 rivers, adhering to fl;ones, but rarely in rapid waters; 

 and of courfe, feldom or ever feen in the mountainous 

 parts, w^here the rivers are tora-ents. In fuch are only 

 to be found the Mya margaritifera, for rarely any other 

 fliell is to be met with where that inhabits, except Patella, 

 Jluviatilis. 



There feems very little doubt that the Nerita laciifiris 

 is a mere variety of this fliell ; the only figure referred to 

 by Gmelin is that given by Gualteri, neither wliich, 

 nor its defcription, give any reafon to fuppofe it diflinft. 



When 



