Book II. DISTRIBUTION OF ANIxMALS. 297 



terranean Sea, including also Armenia and Media; in the fifth, the northern part of 

 Europe, interjacent between Lapland and Paris; in the sixth, the northern part of Asia, 

 where the cold in winter is intense ; in the seventh. North America, Japan, and China ; 

 and in the eighth, all those mountains whose summits are covered with eternal snow. It 

 is, however, easy to perceive, that this, though a very ingenious, is a very artificial theory : 

 the divisions are vague and arbitrary, and we know that animals of one country differ 

 essentially from those of another, although both may enjoy the same degree of tempera- 

 ture. M. Latreille has therefore attempted a more definite theory. His two primary 

 divisions are the arctic and antarctic climates, according to their situation above or below 

 the equinoctial line; and taking twelve degrees of latitude for each climate, he subdivides 

 the whole into twelve. Beginning at 84 N.L., he has seven arctic climates : viz. the 

 polar, subpolar, superior, intermediate, supratropical, tropical, and equatorial : but his 

 antarctic climates, as no land has been discovered below 60 S.L., amount only to five, 

 beginning with the equatorial, and terminating with the superior. He proposes also a 

 further division of subclimates, by means of certain meridian lines ; separating thus the 

 old world from the new, and subdividing the former into two great portions ; an eastern, 

 beginning with India ; and a western, terminating with Persia. He proposes, further, 

 that each climate should be considered as having 24 of longitude and 12 of latitude. 

 This system certainly approxiinates more to what we see in nature than that proposed 

 by Fabricius ; yet Mr. Kirby observes with truth, that the division of the globe into 

 climates by equivalent parallels and meridians wears the appearance of an artificial and 

 arbitrary system, rather than of one according to nature. 



2001. Mr. Swainson considers that the geographic distribution of animals is intimately 

 connected witli the limits of those grand and obvious sections into which the globe is 

 divided ; and that in proportion to the geographical proximity df one continent to 

 another, so will be either the proportional identity or the analogy of their respective 

 animals. He considers Europe, Asia, and Africa as agreeing more particularly in pos- 

 sessing certain animals in common, which seem excluded altogether from America and 

 Australia ; both of which are not only isolated in situation, but their animals have a 

 decided difference of form and habit from those of the three continents of the old world. 

 He considers that the animal geography of Asia is connected with that of Australia by the 

 intervention of Borneo, New Guinea, and the neighbouring isles ; while that of America 

 unites with Europe towards the polar regions. These five great types or divisions will, 

 of course, present certain aflHnities or analogies dependent upon other causes, arising 

 from temperature, food, and locality. (Swainson s MSS.) 



2002. Vertebrated animals have a tvider range than invertebrated animals, thus resem- 

 bling man, who is spread over the whole earth : the dog and the crow are found wild in 

 almost every climate ; the swallow traverses, in a few days, from the temperate to the 

 torrid zone ; and numerous other birds annually perform long migrations. Next to 

 these, insects, above all the other Invertebrktae, enjoy the widest range ; the house fly of 

 America and of Europe are precisely the same ; and Mr. Swainson has observed in Brazil 

 vast flocks of butterflies, which annually migrate from the interior towards the coast. 



2003 Murine animals have, in general, a wider range than those strictly terrestrial. 

 This may probably originate in their being more independent of the eflfects of tem- 

 perature. It is remarkable, that, with the exception of the crow and two or three others, 

 the land birds of America differ entirely from those of Europe, yet that nearly all our 

 aquatic species are found both in the new world and in the southern coasts of Africa. 



2004. Subordinate to the Jive geographic groups already noticed, temperature may he 

 considered the jirincipal regulator of the station of animals ; it has likewise a remarkable 

 influence on their clothing. Many quadrupeds, inhabiting the colder regions, appear in 

 their natural colours during summer, but become white in winter. The same change 

 takes place in the plumage of several land birds ; but is not observable in insects, or the 

 other invertebrate groups. Temperature has likewise a great influence on the size and 

 colour of animals. The iSphinx convolvuli of Europe is found also in India, but of a 

 much smaller size and more distinctly coloured : this is usually the effect of heat upon 

 animals whose chief range is in temperate latitudes. On those which may be con- 

 sidered intertropical, a greater degree of heat not only increases the brilliancy of their 

 colours, but adds to their size. There are many birds and insects common both to 

 central Brazil and Cayenne ; but from the greater heat of the latter country, the 

 specimens are always larger and their plumage more beautiful. Temperature likewise 

 affects the clothing of animals in respect both to quality and quantity. This is more par- 

 ticularly observed in such domesticated animals as have been transplanted from their 

 natural climates. The covering of swine in warm countries consists of bristles of the 

 same form and texture, thinly dispersed ; while the same animals in colder climates have 

 an additional coating of fine frizzled wool next the skin, over which the long bristly hairs 

 project. This difference is very remarkable in the swine of northern Europe and 

 those of tropical America, the latter appearing almost naked : it may be observed in a less 



