28 LECTURES 



will meet my purpose very well to adopt the 

 views in the premises as so ably set forth by Mr. Wallace. 

 As is the case with other departments of science, zoo- 

 geography has grown up from early and crude notions 

 of its principles to its now largely elaborated state. 

 With respect to the occurrence of animal and plant life 

 over the face of the earth, most of our American zoolo- 

 gists divide the land and water areas into divisions in 

 chief which they term "realms," while our British con- 

 freres give the name of "regions" to those areas. But 

 before giving the names of the zoogeographical regions 

 of Wallace, I wish to bring before you some of the gen- 

 eral facts in reference to animal distribution. In speak- 

 ing of the characteristic forms of animal life of any part 

 of the world's land or water areas, we refer to it as the 

 fauna of that part, as in making reference to its plants 

 we speak of them as ihe flora of the same or other parts. 

 We also use special names to designate what classes or 

 groups of classes of animals we may have independently 

 under consideration, as, for example, the birds of any 

 district are referred to as the avifauna of that district, 

 as, are the fishes of any special body of water as its pisci- 

 fauna. Elsewhere I have made use of the convenient 

 term anthropofauna in allusion to the race or races of 

 men that occur in any region, and similar words for 

 other groups will readily suggest themselves to you. 



Now it is a well-known fact that certain classes of 

 animals are practically confined to the dry land, while 

 others are inhabitants of the fresh water, and still others 

 of the salt water; and, lastly, some are common both to 

 waters that are salt and to waters that are fresh. These 

 various kinds not only differ, but still another difference 

 is to be observed in any given locality when we either 

 gradually ascend or descend; that is to say, the flori and 

 fauna at the base of a mountain are usually very differ- 

 ent from the flora and fauna at different elevations 

 on the side of the mountain; and the same holds 

 true for the animals found at various depths 

 in the ocean or great fresh water lakes. Again, divers 

 latitudes, characterized by different climates, have also 

 their characteristic assemblages of plants and animals, 

 and even in different longitudes, where the climates may 

 be almost identically the same, the living populations are 

 again found to be dissimilar. 



Not only do differences of latitude and longitude, dif- 

 ferences of climate, elevation and depths in the water 

 influence the kinds of animals and plants found in those 



