1840.] 



Mammalogij of the Himalayas. 



141 



prosecution of this inquiry ; as, for instance, in tlie case of fresh-water 

 Fishes, than which I am acquainted with no other group of animals ; o 

 well calculated to illustrate the laws of geographical distribution, or so 

 likely to repay a careful study under this point of view; and I am only 

 surprised that no competent Ichthyologist has hitherto occupied himseli 

 with so promising an inquiry. 



The only other principle which can well be regarded as influencing the 

 geographical distribution of Animals, viz. the dispersion of Plants, upon 

 which all Animals live, either mediately or immediately, is obviously sub- 

 ordinate to that of climate, with which it has been shown to be most in- 

 timately connected. On a limited scale the distribution of particular 

 species may be seriously affected by the influence which civilization and 

 cnltivation produce upon the face of particular countries ; wild animals 

 necessarily disappear with the woods and forests which afforded them food 

 and shelter ; the Wolf, the Bear, and the Beaver, have thus disappeared 

 from our own counti'y ; the Capercalzie, exterminated about a century 

 ago, is once more spreading rapidly over the pine forests of Scotland ; but 

 these are partial cases, which do not bear upon the general problem of 

 geographical distribution ; and it is obvious, that upon the great theatre 

 of nature, climate and temperature are the only laws which regulate it, 

 limited, indeed, by the physical structure of the animals, as has been al- 

 ready observed, and by their powers of transporting themselves to dis- 

 tant regions. Hence it is that teiTestrial and fresh-water tribes are more 

 favourable for this study than marine or pelagic ; though even among the 

 latter, the comparative simplicity of their structure, and their consequent 

 susceptibility of changes in temperature, render the habits of different 

 genera and species more definite and confined than might otherwise be 

 expected. Of the former, again, land and fresh -water Mollusks being 

 among the most simply organized, are consequently most limited in point 

 of range ; the species of Insects are almost equally confined, unless in the 

 case of certain tribes, which are susceptible of being transported to distant 

 countries in wood and other extraneous substances ; next follow Reptiles 

 and fresh-water Fishes ; and, last of ail. Birds and Mammals ; the former, 

 as already observed, having an almost unlimited range of habitat, from 

 the facilities which they derive from their powers of flight, of passing to 

 the most distant quarters of the globe. The common Sparrow, the Snipe, 

 and the Woodcock, for instance, are found in the Himalayas ai)d in Japan, 

 as well as in the North of Europe ; nature has endowed these birds with 

 means of traversing the arid climes and extensive deserts which intervene 

 between these localities, which she has denied to Quadrupeds ; and hence 

 we must not expect to find the Badger and the Fox so widely distributed 



