GENERAL ERRORS. 35 



be observed even by the careless and inattentive looker-on ; 

 much more is it to be expected that the habits, nay, the sexes, 

 ages, and distinct species of fish, which rarely present them- 

 selves to the eyes even of the most curious inquirers, which 

 come and go unseen and unsuspected, whose mysteries of gene- 

 ration and reproduction are all performed in a medium the 

 least penetrable to the eyes of science, whose changes of size 

 and colour, from infancy to maturity, pass utterly beyond our 

 ken, should have been misconceived, misinterpreted, and 

 misdescribed. 



Within the last few years more has been done to elucidate 

 these mysteries, and to bring us to an accurate knowledge of 

 this interesting portion of the animal creation, than in many 

 previous centuries ; and although much yet remains, infinitely 

 more, doubtless, than has been done, still we have very recently 

 attained much certain knowledge regarding several of the most 

 interesting families ; we have arrived at results which, by simple 

 deduction, show us how we may hope to arrive at more, having 

 now obtained data wherefrom to advance and discover the 

 process by which to do so. 



The means by which thus much has been accomplished, may 

 be described briefly, as the taking nothing for granted, 

 assuming nothing on hearsay beyond facts, and on investigating 

 everything carefully and painfully, not following too readil}^ 

 preconceived opinions, nor being misled by mere external and 

 superficial resemblances, but being guided by comparison and 

 experiment, as founded in a great degree on anatomy and 

 osteology. 



In the examination and comparison of fishes, the clear 



D 2 



