4786 Fishes. 



teeth on the anterior part of the vomer, and a double row behind, 

 and herein is directly contrasted with the British lake species. In 

 the common trout of New York there is a triangular cluster of about 

 ten teeth on the anterior part of the vomer : no mention is made of any 

 posterior rows. Such exceptions could be much multiplied ; they are 

 sufficient to prove that a dentar formula applicable to the adult Sal- 

 monidae of all species has not yet been found. 



Section II. 



As it is by the exterior and not by the interior, that Nature chiefly 

 specializes all animals, bestowing on them those outward forms, 

 colouring and proportions, by which they are known to men and ani- 

 mals, — enabling man to distinguish at a glance the lion from the tiger, 

 the zebra and ass from the horse and mule, the dog from the fox and 

 wolf, which the interior, though examined by the profoundest anato- 

 mist that ever lived, scarcely enables him to do, — so I return to the 

 exterior of the Salmonidse to look for other proofs of the existence of 

 the law I now seek to establish ; the law by which I endeavour to 

 give the genus or natural family a real existence ; to reduce it to 

 materiality ; to include it within the range of legitimate science, and 

 to submit it to intuitive or direct inspection ; to prove, in fact, 

 the young to be of no species, a generic being, invisible as such to the 

 bulk of mankind, but real, tangible and visible to the scientific. 



Coloration of the Salmonidm. 



The system of coloration of the Salmonidae is either specific or 

 generic. When the individual is in prime condition, perfectly 

 developed, pure in breed, and adult, in as far as we can well deter- 

 mine, the coloration may then be considered specific, may be 

 assumed as unalterable, in a certain sense, and characteristic. Viewed 

 in this way, the coloration, 1st, of the true salmon may be briefly de- 

 fined as silvery scaly, with a few dark or purple spots above the late- 

 ral line ; 2nd, of the forelle, less silvery, with numerous dark spots 

 above and below the lateral line ; 3rd, of the lake trout, dark or 

 purplish spots, more or less numerous, above and below the lateral line, 

 and of the river trout, red spots more or less numerous above and be- 

 low the lateral line. Lastly, certain river trout retain throughout life 

 transverse bars composed of numerous minute dark spots ; these I 

 shall call parr-markings, as they are most distinct in the little fish 



