FISH IN GENERAL. 35 



their prey, such as the toxotes and chastodon rostratus, who 

 bring down insects for prey by blowing a drop of water upon 

 them to some distance : but all these differences of habit, 

 may be principally ascribed to differences of conformation, 

 and it would be vain to attempt an explanation of them 

 without a particular study of all the parts of the body offish, 

 the differences between their structure and that of other verte- 

 brated animals, and the modifications it undergoes in different 

 families, genera and species. 



Thus far we have chiefly followed our author in his 

 general view of the nature and organization of fish, but before 

 we offer his concluding observations it may be agreeable to 

 the reader to find some further remarks, equally the result of 

 conformation, and applicable only in considerations which 

 embrace the whole class, such as respect the geographical 

 distribution, the nature of the residence, the migrations of 

 fish, their powers of vitality, &c. 



DISTRIBUTION, HABITAT, MIGRATIONS, &c. OF 



FISH. 



The watery element where fish were appointed to reside, 

 not being, as already noticed, liable, like the atmosphere, to 

 great and rapid alternations of heat and cold, and the blood 

 of fish remaining in a temperature often lower than the sur- 

 rounding fluid, none of the greater divisions of this class of 

 animals are so strictly confined to either high or low latitudes 

 as those of others breathing the air. But there is a circum- 

 stance affecting fish, to which in their turn animals with 

 lungs are strangers ; namely, the difference in density and 

 chemical properties between fresh and salt water ; the 



D 2 



