DISTRIBUTION OF SPECIES. 19 



beaver/ all of which have, consequently, a very extended range. 

 The American panther or couguar (Felis concolor) inhabits the 

 territory included between Canada and Patagonia, an extent cover- 

 ing upwards of one hundred degrees of latitude, which probably 

 represents the greatest north and south range of any mammal. 



As might naturally have been expected from the greater facili- 

 ties for dispersion, we find many more marked instances of broad 

 specific distribution among birds than among mammals. Indeed, 

 when we consider with what apparent facility certain birds accom- 

 modate themselves to the varying conditions of atmospheric pres- 

 sure and climatic changes, and the readiness with which they trav- 

 erse broad expanses of the oceanic waters — e. g., the North Atlantic 

 between Ireland and Labrador — it might at first sight appear as 

 though there ought to be, at least in many cases, no absolute limit 

 to their distribution ; yet, from our present knowledge, it may 

 safely be afllrmed that there exist but very few species of birds 

 which are in any way cosmopolitan. The fish-hawk (Pandion 

 haliaetus), with probably the most extensive range of any known 

 bird, inhabits the greater portion of all the continents, with the 

 possible exception of Australia, where its place appears to be supr 

 plied by a closely-allied (and by many ornithologists considered 

 identical) species, the P. leucocephalus. Scarcely, if at all, less 

 extensive is the range of the common peregrine falcon (Palco com- 

 munis or peregrinus) and the barn-owl (Strix flammea), the former 

 of which is distributed, according to Professor Newton, from " Port 

 Kennedy, the most northern part of the American continent, to 

 Tasmania, and from the shores of the Sea of Okhotsk to Mendoza, in 

 the Argentine territory," and the latter, according to Sharpe, over 

 the entire world, with the exception of New Zealand, and many 

 island groups of Oceania, Malaysia, &c. The common American 

 raven (Corvus corax) has, likewise, a very broad distribution, its 

 range extending from Mexico into the far north, over the whole of 

 Europe and Northern and Central Asia, as far east as the Island of 

 Saghalien. 



The fishes present scarcely less well-marked examples of broad 

 distribution; but in such aquatic forms the physical conditions of 

 the medium which they inhabit offer far less obstacles to a very 

 general diffusion than are to be encountered in the case of terrestrial 

 animals. The same holds true with other aquatic animals capable 



