GENERAL CLASSIFICATION OF FISH. 39 



through which the water from each gill escapes. 

 They have also small cartilaginous arches suspended 

 in the muscles opposite the gills, which may be 

 called gill-rihs. They form two Families. 



The foregoing eight Orders are again subdivided into 

 Families, Genera, Species, &c., as already stated. 



The following List exhibits in a tabular form the classi- 

 fication above explained, with the addition of the names of 

 the various Families : — 



