SHELLS AND MOLLUSCOUS ANIMALS. 209 



parts of our shores. It has a thin glossy skin over 

 it, of a chestnut brown colour, but when this is 

 rubbed off, we see it to be beautifully marked and 

 of a pale purple tint ; and it is capable of receiving 

 a high polish. Several other species inhabit the 

 British seas. The Golden Venus ( Venus aurea) is 

 a shell, about one inch and a half long, of a beau- 

 tiful golden yellow. Several of the species of this 

 genus pierce stones and masses of coral, and the 

 boring rock Venus is a native of many of our 

 rocky shores. 



Some very pretty little shells of the Donax 

 family are among the very commonest of those 

 which we meet when we ramble along the sands. 

 They may be described as triangular, flattened and 

 wedge-shaped. These shells bury themselves in 

 the sand, often to the depth of sixteen fathoms, 

 with the short end of the shell uppermost, in order 

 to admit the entrance of the sea-water, through 

 the respiratory siphons of the animal within. 

 Our figure represents a shell often found when the 

 tide has receded from the 

 sands, and there are few sandy 

 shores along our island, where 

 it is not plentiful; it is the 

 truncated Donax (Donax trun- 

 culus], an oblong, glossy shell, with fine thread- 

 like lines, from the base to the hinge, which are 

 crossed by purple bands, and also rayed with purple. 

 The interior is white, often tinged with a purplish 

 hue, and the edges of the shell are finely notched 

 with little rounded notches. It is, on this account, 

 commonly called the saw-shell. Some other of 

 our British Donaces are more distinctly wedge- 

 shaped than this. They are all small shells. 



