21 



spirits, which will, at least, preserve a certain 

 portion of their characters. 



CLASS 4.-ACARL 



THE bodies of the Acari are formed but of 

 one segment ; the mouth is ros triform, and in 

 some is furnished with maxillae and mandibles ; 

 the legs six or eight: trachece for respiration. 

 [PL I, fig. 7.] 



Most of the Jlcari are parasitic, and numbers 

 will be found on aquatic animals, especially 

 amphibious quadrupeds ; they also attach them- 

 selves to fishes : most quadrupeds are attacked 

 by them, and man does not escape ; insects are 

 also much annoyed by them, being sometimes 

 completely covered with these animals : the 

 dog-tick and cheese-mite belong to this class. 

 Many of the species are confined to the water, 

 their legs being formed for swimming; they are 

 extremely brilliant in colours, and most beau- 

 tifully marked: they are chiefly found in clear 

 fresh waters. Like spiders, they must be pre- 

 served in spirits. 



CLASS 5. INSECTA. 



THE class Insect a, or Insects, is by far the 

 most numerous of all the classes of the annulose 

 animals, there being, at least, 100,000 species 



