ON NORTH AMERICAN ZOOLOGY. 135 



history appendix to Captain Beechey's voyage by Mr. Vigors 

 is our principal authority for the Californian birds; while the 

 only professedly complete view of the Mexican fauna is the al- 

 most obsolete work of Hernandez. European museums, that 

 of Berlin especially, have since the overthrow of the Spanish 

 dominion in the New World obtained many specimens from 

 Mexico, but we have not been able to procure a complete list 

 of species, nor has the Prodromus FauncB Blexicance announced 

 by Professor Lichtenstein yet reached England. In the mean 

 time we have had recourse to that author's elucidations of Her- 

 nandez {Abhandl. der -de. der Wissensch. zu Herlin, 1827) > 

 to Deppe's sale list of Mexican specimens collected by himself, 

 and M. Schiede, dated 1830; and to a paper by Mr. Swainson 

 in the Philosophical Journal for 1827, describing one hundred 

 species of Mexican birds: but as these papers do not notice 

 the range of tlie species^ they are very imperfect substitutes for 

 Professor Lichtenstein's expected work. 



From the geographical position of Mexico on the verge of 

 the tropical region, the peculiar physical configuration of its 

 surface, and its being the boundary between the northern and 

 southern zoological provinces of America, it is the region which 

 above all others is likely when properly studied to yield infor- 

 mation respecting the laws which influence the distribution of 

 animals. This has been well shown by Professor Lichtenstein 

 in his paper in the Berlin Transactions already quoted. He 

 compares the whole of New Spain to a great mountaiuj, whose 

 volcanic summit, attaining an elevation of 17,000 feet, enters 

 within the snow line*, while its middle, temperate region 

 is traversed by numerous valleys communicating at various 

 heights, with wide basins, whose bottoms are little more than 

 a thousand feet above the sea level. Hence the traveller jour- 

 neying down the deep descent of one of these magnificent ra- 

 vines through forests of beeches, oaks, and pines loaded with 

 cacti and epidendra, finds himself suddenly on the level shores 

 of the Rio Alvarado surrounded by palms, and has an oppor- 

 tunity of seeing the animal productions, of the north and 

 south, of the alpine regions and tropics, nay of the eastern and 

 western hemispheres, mingled together. Wolves of northern 

 aspect dwelling in the vicinity of monkeys ; humming birds 

 returning periodically from the borders of the frozen zone with 

 the northern buntings and soft-feathered titmice to nestle near 

 parrots and curucuis ; our common European whistling ducks, 



* The observations of Humboldt place the inferior limit of perpetual snow 

 within ten degrees of the equator in America at about 16,000 feet. 



