Fishes. 4605 



the vomerine teeth in the Salmonidae, I have ascertained to be thus : 

 when young, all the species of the three subfamilies, into which the 

 Salmonidae may, for the convenience of description, be subdivided, 

 have the same dentition, which, as regards the vomerine teeth, con- 

 sists in a double alternating row of teeth, with a few transverse teeth 

 in front upon the fore part of the vomer.* As the fish grows the great 

 generic character and law yields to the law of specialization and of 

 family. Thus, as regards the Salmonidae, if the young fish is to grow 

 into a true salmon, it loses the vomerine teeth from behind forwards, the 

 transverse teeth in front being those which remain to the last. This, 

 in fact, is the special character of the dentition of the true salmon, 

 and the law which regulates it. If, on the other hand, the young fish 

 is to become a sea trout or Fario (a subfamily strongly allied to the 

 true salmon by some species, and as strongly no doubt with true trout 

 on the other), it also loses the vomerine teeth from behind forwards, 

 but retains a few occasionally in a single row, the transverse or front 

 vomerine remaining as in the salmon; but if the young fish is to 

 grow up a trout, then the transverse teeth, always few in number, either 

 remain as they were or are lost, the double alternating row continues, 

 and the bone becomes edentulous from before backwards. Which 

 form prevails in the estuary trout I know not ; I should think the 

 latter; but, be this as it may, the estuary trout seems to me to fill 

 up that link in the grand serial chain of the Salmonidae, connecting 

 the river trout with a fish of the salmon kind which appears in the 

 markets occasionally in September, — a fish not yet well described nor 

 placed ; the red or purple-spotted salmon. 



In thus describing the characteristic dentition of the three sub- 

 families of the Salmonidae at present known to zoologists, I do not 

 pretend that such distinct* lines of demarcation absolutely exist in 

 nature. To us they seem real, and so far are real, because we know 

 no better ; but, in the great scale of Nature, there are in reality no 

 such things as species or subfamilies, all gaps being no doubt filled 

 up, did we but know sufficiently the fossil and the recent zoologies. 

 Generic distinctions seem alone to exist and to be recognised in 

 Nature's scheme, and some distinguished anatomists are disposed to 

 doubt even this. In the mean time, for the sake of classification and 

 in the interests of science, these characters of subfamily and species 

 answer well enough. 



In August the milt in some specimens was found to be largely 



* Chevron of French naturalists. 



