GREA T BRIT A IN. 5 7 



undisturbed, geologically considered, for a long period. 

 Almost everywhere at 500 fathoms, everywhere at 1000 

 fathoms, there is almost an entire absence of currents in 

 the water ; any movement must be of a molecular nature 

 only, excessively slow and quite imperceptible to animals ; 

 while the conditions of life, at least from 500 fathoms 

 downwards, do not show any zones of distribution in its 

 fauna. Deep sea, or abyssal forms as already remarked, 

 have large eyes, or may be entirely blind. 



Irrespective of the fish which more or less continue in 

 our seas throughout the year, wanderers or occasional 

 visitors are likewise captured ; some of these are cosmo- 

 politan in their habits, others are residents in the colder 

 north, from whence they may have wandered at first perhaps 

 in the under-flow from the Arctic Ocean ; or we may have 

 species along our south or east coast mostly during the 

 summer months from the Mediterranean, or ascending 

 along our western shores with the Gulf Stream from the 

 more sunny south. The distribution of the various genera 



and species will be detailed further on. 



i 



BRITISH FISHES. 



SUB-CLASS I. BONY FISHES OR TELEOSTEI. 

 ORDER I. SPINY-RAYED FISHES OR ACANTHOPTERYGII. 



FAMILY I. PERCHES (Percidce}. 

 GENUS I. Sea Perches (Labrax, Cuvier). 



Geographical distribution. This marine, and in some 

 localities river, form of perch extends from the Arctic 

 regions in Europe to the Mediterranean and Egypt ; also 

 along the coasts of North America ; while one species has 

 been taken at the Celebes. 



