192 



N. with a comprefl'ed, fub-carinated, fpiral, fmootli, 

 glofTy, pellucid, horn-coloured fliell ; fometimes rufous- 

 brown : the upper fide convex ; apex deprefTed, concave, 

 w'ith tliree vifible volutions, and a fourth loft in the de- 

 prefTion ; thefe are bordered on their outer edge with an 

 opaque, whitidi line, or band, that runs fpirally to the 

 centre at the junftion of the whirls: under fide flat, and 

 deeply umbilicated : concamerations dillant; joints or di- 

 vifions, only three vifible in the exterior volution ; thefe 

 are nearly equidiftant, and appear like fo many curved, 

 white lines, radiating from the Umbilicus, and are the 

 fhades of ihcfepta, or plates that divide the chambers. 



The firft of thefe divifions is placed a confiderable way 

 M'ithin the aperture, the third at about two-thirds the cir- 

 cumference : between the firft two divifions is fometimes 

 a firong wrinkle, of a deeper colour than the reft of the 

 fhell : aperture narrow, fub-cordate, clafping the body 

 whirl on both fides nearly equal; but the edge, or margin, 

 flopes obliquely to the flat or under fide. Diameter two- 

 lenths, rarely a quarter, of an inch, 



Mr. Walker was the firft who noticed this fiiell, but 

 had overlooked the very fingular ftruflure of its internal 

 parts ; and indeed we might have fuppofed he had intend- 

 ed the //(?/z\x ybM;^<2?i(2, but that he exprefsly fays, "The 

 lincated fnail, with two central, white lines, crofting the 

 Umbilicus. Thefe are the two nioft. confpicuous divifions ; 

 and, frequently has no other perceptible ones. 



Mr. Light- 



