SHELLS AND MOLLUSCOUS ANIMALS. 191 



whitened by sunshine and rain to the colour of 

 snow, crowded sometimes with the twisting shelly 

 tubes of the Serpula, or pierced in a thousand 

 holes by minute sea-worms, or forming a ground- 

 work for a little grove of plant-like corallines, or 

 for the mossy tuft of sea-weed. A strong and 

 tough shell it is also, and useful, as we see, to other 

 animals besides the one which made it for its 

 dwelling. We all know the worth of the inmate. 

 The Greeks and Romans valued the oyster very 

 highly, and their epicures spared neither trouble 

 nor expense to procure those which they considered 

 the finest flavoured kind. They were good judges 

 too, if we may trust the satirist Juvenal, who, in 

 describing an epicure, says : 



" He, whether Circe's rock his oysters bore, 

 Or Lucrine Lake, or distant Bichborough's shore, 

 Knew at first taste." 



They procured them from the Dardanelles, from 

 Venice, from the Bay of Cumse, and from England, 

 and valued most those which were brought from 

 different lands, and afterwards fattened in the 

 Lucrine Lake. It was a Roman also, Sergius 

 Grata, who first thought of this plan of making 

 artificial beds, and turning oysters into " natives." 

 Oysters dwell in the ocean, some lurking in the 

 sands, others adhering to rocks; while on the 

 shores of the West Indies, a species attaches itself 

 in thick clusters to the large roots of the mangrove 

 trees, which grow in groves around the sea. The 

 finest edible oysters are those of Britain, and they 

 are frequent on many parts of the shores of this 

 island. At Milton, in Kent, as well as many 

 other places, large beds are formed of them. They 



