394 New Publications. 



contents of all other circles in the same class of animals ; this 

 resemblance being strong or remote, in proportion to the proxi- 

 mity or the distance of the groups compassed. 3. The pri- 

 mary divisions of every natural group, of whatsoever extent or 

 value, are three^ each of which forms its own circle. 



Dr Richardson, whose mind seems more inclined to the prac- 

 tical than the theoretical, has limited his labours to the task of 

 clear and accurate descriptions of the species, with occasional 

 observations on their history and habits of life, their migrations 

 and geographical distribution. In illustration of the last-named 

 topic, he has also constructed several valuable tabular views of 

 the species, exhibiting their extreme northern range, their great- 

 er or less extension over the Fur Countries, their winter and 

 summer habitations, and other particulars of great value and in- 

 terest. The eleventh table contains a list of species common to 

 the Old World and the Fur Countries of America, under which 

 term may be comprehended generally the whole country north 

 of the 48th parallel of Latitude. The analogous list given 

 by Pennant in his Arctic Zoology, though a valuable contribu- 

 tion for the period, is vague and inaccurate in relation to the 

 knowledge which has been more recently acquired, and hence 

 the high importance of the information now communicated by 

 Dr Richardson. It may, in truth, be said that the Ornithology 

 of North America is almost as well known as that of Europe. 

 The works of Wilson, Audubon, and C. L. Bonaparte, con- 

 joined with the kindred labours of the authors now under re- 

 view, form a mass of ornithological information not excelled in 

 interest by that supplied by the writers of any other country. 



It appears, from a comparison of tables furnished, that the 

 number of ascertained birds in Europe and North America is 

 at present nearly the same. There are from 390 to 400 de- 

 scribed species in each continent *. As, however, a greater 

 portion^ of North America than of Europe remains to be yet 

 more minutely explored, we may infer that, eventually, the 

 European species will form the smaller number. The Euro- 

 pean land birds appear to exceed the water birds and waders 



• If the investigations of Brehm, as explained in the Isis, and detailed in 

 his valuable " Handbuch der Naturgeschichte aller Vogel Deutchlandes," 

 shall prove correct, the number of European species of birds will be much 

 increased. 



