436 PATELLIDiE. 



itself, which is rather flattened, exhibits the external 

 colouring, and often presents an articulated appearance ; 

 the spatula, or central mark, is more or less stained with 

 brown, and the intermediate portion is enamelled with 

 porcelain or bluish white. The edge is acute and quite 

 entire. 



The animal is entirely white ; the margin of the mouth 

 has considerable expansion, and is fringed with minute 

 white cirrhi, which are quite inconspicuous when it is 

 taken out of the water. The head bears two rather long 

 and slender tentacula, having eyes at their internal bases. 

 When the creature is active, the long lanceolate branchial 

 plume is conspicuous, projected from its cavity on one 

 side of the head, and extends some distance even beyond 

 the shell. The disk of the foot is oval and very broad, 

 and the sides quite plain and not steep. The tongue 

 is long and is divided into a series of sections, each com- 

 posed of two squares, the centres of which are of a bright 

 yellow. On each square there are two conspicuous hooked 

 teeth and a denticle, and the upper angles are produced. 



This Mollusk is a northern species of littoral habits, 

 and does not make its appearance on the southern coasts, 

 if indeed anywhere on the shores of England and Wales, 

 though, as it appears to have a tendency to migrate 

 southwards, it may be found hereafter considerably beyond 

 the limits we here assign it. The locality " Bangor, 1 ' 

 assigned to it by Mr. Sowerby, refers not to Bangor in 

 North Wales, but to a place of the same name in the 

 north of Ireland. On the Irish shores it has found its 

 way as far south as Dublin Bay, in which well-searched 

 district it has been noticed only of late years ; it is there 

 " abundant, near Williamstown, on stones above low- 

 water-mark " (Hassall). It has appeared since 1836, and 



