149 



Mr. Donovan is certainly ri;ht in conjecturins^ that his 

 J^erita idtrtcata is a variet)' of .V. canrcr.a ; and wh'ch ac- 

 cording to the opinions of Teftaceoljgical writers are innu- 

 merable in their variation with respefl to markings. 



Tiie fpecimen we were favoured with by Mr. Donovan 

 differs very little from the figure he has given, and is greatly- 

 like fome Tpecimens of JV. glaua'na ; intleed fo much do 

 thefe fhells refemble each other, tliat a feparate defcrlption 

 is needlefs, as the di(tin6lion principally confilts in the dif- 

 ferent formation of the umbilicus. The fhell before us is of 

 a livid, or purplifh flefh-rolour, with catinated bands of 

 mixed ferruginous and white : the umbilicus is furnifhed with 

 two fpiral ridges, and two grooves, corrr'fponding with the 

 Gmeliniau character " umbilico gibbo bifida." Diameter of 

 Britijb fpecinensnot much more than half an inch. Said 

 to be found at fVcymoiUh, but we conclude very rare. 



Nerita Pes Elephantis. Chem. Cotich. v. t. 189. f- 1922 — 23. Nitida. 



Lister Cotich. t. 571. f. 22. 

 Lin. Tra?is. viii. p. 225. 

 Nerita nitida Don. Br. Shells, iv. t. 144. 



This is another fpecies of iN'erita, very much refembling 

 in fliape the glaucina, but the fuperior volutions are not placed 

 fo lateral, and differs a little in the umbilicus, which is half 

 clofed, or lunated : the colour is pure white, and extremely 

 glofly. Diameter fcarcely half an inch. 



We 



