FAUNA BOREALI-AMERICANA.
THIS is the first zoological work ever published under the im- mediate authority of the British Government ; and we are glad to pronounce it worthy, in all points, of dais high but tardy patron- age. It is a very learned and at the same time a very splendid performance. The subject is one of extreme interest in itself; and it has been elucidated by the application of great industry and. intelligence, chiefly as regards the Birds, by one of the first ornithologists. Mr. SWAINSON has not been content with the description of the specimens placed before him for that purpose; but he has sedu- lously examined them with a view to the development of a sys- tem of nature, which, for the last twelve years has been the sub- ject of much investigation, and among naturalists of a very general adoption. The system originated with the younger MACLEAY; and if it has not got a name, it may be called the Circular System. According to it, the affinities of all natural beings fall into circles, —that is, may be divided into classes, the individuals of which vary in such a manner that their variations have a continual tendency to return to the same point, and ultimately do return. This theory is thus expressed by Mr. SWAINSON-
" Every natural series of beings, in its progress from a given point, either ac- tually returns, or evinces a tendency to return again to that point, thereby form- ing a circle.'
In other words, if you take any series of natural beings, and look to their points of difference, you will find that on tracing the differences from individual to individual, you are brought back again to the point you started from, by the circular or returning nature of the affinities existingin and binding together the series in question. . This theory has not yet been, and perhaps never can be actually demonstrated, by an universal examination of nature : but as far as it has been, the confirmation of it is truly wonderful; we know not a more beautiful inquiry.
Mr. SWAINSON has adopted this fundamental principle; but in taking the next steps in the conduct of the system, he differs from the idea of the founder and most of his followers. The primary division of all natural groups is, according to Mr. MACLEA.Y, five—with Mr. SWAINSON, three : the first is the quinary system, the second the ternary. Besides this change, much more im- portant than it appears on the mere enunciation, Mr. SWAINSON would establish another important difference : he makes what he calls the theory of representation, the test of the naturalness of the formation of any group. This principle Mr. SWAINSON states as follows- " The contents of each circle or group are symbolically represented by the contents of all other circles in the same class of animals; this resemblance being strong or remote in proportion to the proximity or the distance of the groups compared."
Thus, all nature seems to be connected in mysterious links, each link having a greater or less relation to other links, according to its proximity or distance in the order of nature. The mere form of these links has been only lately suspected,—certainly is not yet arrived at; but great progress has been made, and all subsequent careful investigation of the theory seems to confirm it. Every day produces to the industrious and intelligent naturalist some new fact, which both gives and takes a flood of light from being viewed merely in connexion with it.
The Birds of the Arctic Regions, which are here described, drawn, and illustrated in every form, were chiefly collected in the land expedition to the Northern extremity of America by Dr. RICH- ARDSON. By whom the drawings are made, is not stated : they do great credit to the artist : they are full of life and spirit, and seem all on the wing. The plates are very numerous, and beauti- fully coloured.
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