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202 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 flights 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 peculiarities.

As in the Acanthopterygian Order, we give from the Prince of Canino's Synopsis a list of the twelve Families included in the, with the number of species included by him in each Family, at the time (1831) when it was published. As we go through the Families in course, we shall mention the number of species assigned