202 MALACOPTERYGII. 



employment to myriads of industrious people, 

 and the fountains of commercial wealth to towns, 

 districts, and even nations ; of these we shall have 

 to speak somewhat in detail. 



In general there is but one dorsal fin present in 

 this Order : some of the Cods indeed are described 

 as having three, but we rather incline to consider 

 these as divisions produced by interruptions of 

 continuity in one lengthened fin; just as the 

 finlets in the typical Mackerels are structurally 

 nothing more than the posterior portions of the 

 second dorsal and anal cut into notches. The 

 Salmons have a minute second dorsal, commonly 

 called the adipose; but it is not a true fin in 

 structure, being only a lamina of fat inclosed in 

 a fold of skin, quite destitute of rays. 



The most singular aberrations of form and 

 function that we meet with in this Order are 

 found in the Flying-fishes, and in the Flat-fishes. 

 The former, by an enormous development of 

 some of their fins, are able to take long fiights 

 through the air like birds : the latter have a most 

 remarkable contortion of the body, whereby the 

 usual symmetry of form and organs and colour is 

 lost. Both of these peculiarities will require 

 special notice in their proper order. The large 

 Family of the Eels also presents interesting pecu- 

 liarities. 



As in the Acanthopterygian Order, we give 

 from the Prince of Canino's Synopsis a list of the 

 twelve Families included in the Malacopterygii, 

 with the number of species included by him in 

 each Family, at the time (1831) when it was pub- 

 lished. As we go through the Families in course, 

 we shall mention the number of species assigned 



