DON AX. 405 



at the height (accurately ascertained) of from 1330 to 

 1360 feet above the present level of the sea, together 

 with about fifty other species of shells mostly of an arctic 

 character ! (Darbishire) ; Mammalian Crag, Bramerton 

 (S. Wood) ; Sicilian tertiaries (Philippi). M 'Andrew has 

 taken it on the coasts of Upper Norway in 3-25 fathoms ; 

 I noticed specimens from Jutland in the Royal Museum 

 at Copenhagen; and southwards it occurs from Schel- 

 ling on the Dutch coast to Vigo, as well as in the Me- 

 diterranean, ^Egean, and Black Sea. 



Marvellous accounts have been given of the agility of 

 this little shell-fish, one of them being that when it is 

 taken out of the sand it will endeavour to regain the sea 

 by a succession of well-directed leaps. It certainly can 

 twist itself about almost as actively as Nassa neritea 

 does in the lagunes of Venice ; and that is saying a good 

 deal for it. The fry have triangular shells, with the 

 posterior end more rounded and the beaks prominent ; 

 in this stage of growth it is the D. rubra of Turton. A 

 specimen in my cabinet is inequivalve, the left valve 

 overlapping and partly enveloping the other, as in Cor- 

 bula. The colours of this shell do not soon fade ; they 

 are, as Tennyson says, of the kind 



" That keep the wear and polish of the wave." 



This is the D. trunculus of Linne*, although his re- 

 ferences to the works of Adanson, Buonanni, Klein, and 

 Argenville belong to an allied species which now gene- 

 rally bears that name. His descriptions in the ' Fauna 

 Suecica' as well as in the tenth and twelfth editions 

 of the ' Systema Naturae ' exactly apply to the present 

 species ; and the first authority which he cites is Lis- 

 ter's ' Treatises on English Animals/ Da Costa finds 

 fault with these inconsistent references ; but he seems 



