ORDER CRUSTACEA HOMOBRANCHI^. 117 



upon any animal substance, putrid or not, that may 

 come within their reach. Some of the species are well 

 known as articles of food, but they are not equally whole- 

 some at all seasons of the year. 



THE CRAB TRIBE. 



The genera of the Crustacea are so extremely numerous, 

 and the knowledge we possess of their natural history 

 is so scanty, being generally confined to their form and 

 colour, that we shall limit ourselves to a description of 

 some of the best known and most useful species. 



THE ZOEA OF THK COMMON CRAB. 



The Crabs are a very numerous tribe, and contain 

 many singular species, as far as regards their form. 



