18 FISHES. 



brought together a collection the like of -which had never 

 been seen before, and which, as it contains all the materials 

 on which his labours were based, must still be considered 

 to be the most important. Soon after the year 1820, Cuvier, 

 assisted by one of his pupils, A. Valenciennes, commenced 

 his great work on fishes, " Histoire natureUes des Poissons," 

 of which the first volume appeared ia 1828. The earlier 

 volumes, in which Cuvier himself took his share, bear evi- 

 dence of the freshness and love with which both authors 

 devoted themselves to their task. After Cuvier's death in 

 1832 the work was left entirely ia the hands of Valenciennes, 

 whose energy and interest gradually slackened, to rise to the 

 old standard in some parts only, as, for instance, in the treatise 

 on the Herring. He left the work unfinished with the twenty- 

 second volume (1848), which treats of the Salmonoids. Yet, 

 incomplete as it is, it is indispensable to the student. 



There exist several editions of the work, which, however, , 

 have the same text. One, printed in 8vo, with coloured or 

 plain figures, is the one ia common use among ichthyologists. 

 A more luxurious edition in 4to has a different pagiuation, ' 

 and therefore is most inconvenient to use. 



As mentioned above, the various parts of the work are 

 very unequally worked out. Many of the species are de- 

 scribed in so masterly a manner that a greater excellency of 

 method can hardly be conceived. The history of the-litera- 

 ture of these species is entered into with miuuteness and 

 critical discernment ; but in the later volumes, numerous 

 species are introduced into the system without any descrip- 

 tion, or with a few words only, comparing a species with one 

 or more of its congeners. Cuvier himself, at a late period of 

 his life, seems to have grown indifferent as to the exact defini- 

 tion of his species : a failing commonly observed among 

 Zoologists when attention to descriptive details becomes to 

 them a tedious task. What is more surprising is, that a man 



