so CLASSIFICATION OF FISHES. 



CHAP. III. 



ON' THE MICROLEFTES, Oa SMALL-SCALED TK.IBE OF THE 

 ACANTHOPTERTGIOUS FISHES. 



(31.) The second tribe of the spine-finned order, 

 although very niunerous_, is inferior to the last. To man- 

 kind, however, it is of much more importance, since it 

 contains all those of the order before us, which form the 

 object of peculiar fisheries, in which respect it is ana- 

 logous to the SalmonidcE among the ground-fish. The 

 different species of tunny and of the mackerel are 

 placed at the head of this tribe, the fisheries of which, in 

 the Mediterranean and in Britain, employ many thousands 

 of people and a vast amount of capital. The structure 

 of these fishes, indeed, will give a tolerably good idea 

 of nearly all those which constitute our present di- 

 vision. Having already pointed out their peculiar 

 characters, we may at once proceed to indicate the pri- 

 mary groups into which they appear naturally to be 

 arranged. The two great typical families are the 

 ScomheridcE, or mackerels, and the Centronotidce, or 

 spinebacks. With these we place, as aberrant, the Cory- 

 phcBiiidcE, or dolphins^ the CentriscidcE, or trumpet-fish, 

 and the Echeiieidcs, or remoras. By far the greater 

 part of the species are comprised in the two first, — an 

 inequality which we have seen to be uniform throughout 

 the whole class, as well as in the great divisions of the 

 verteorated circle. Yet there is such an evident ten- 

 dency of these aberrant families to approximate to this 

 tribe more than to any other, that however wide the 

 intervals may be between some few which, on that 

 account, appear in this and all other systems, to be 

 isolated, yet we are not without valid induction for 

 viewing them as congeners of the more typical groups. 

 We shall therefore at once arrange these divisions in a 

 column, and point out their analogies. 



