14 INTRODUCTION. 



Sub-kingdom, Vertebrata. ■ 



Class, J/ammalia. 



Order, Varnimra. 



ramily, Caniilic. 



(4enu.s, C'n/iis. 



Species, f_a/;/-s" fftiiiiUiwis. 

 In an ordinary way, Imwever, it is ijviite nnnecessary to emploj' in 

 practice any of the aliove names except the last or speeific nxaae, 

 since that implies all the others. 



The remainder of this work will be occupied with the considera- 

 tion of the chief characters of the more important groups into which 

 the animal kingdom has been divided, omitting those which are not 

 of paramount interest ; but it will be necessary fir.st to say a few 

 words as to the distriljution of animals in sjiace and in time. 



"i. Distribution of Animals in Si'Ace and in Time. 



Distribution in Space. — The distributii:>n of animals in space, or 

 t\\eiv tfi'iir/nt/i/iii'iil (lixtrihutiiiii, is a department of zoology which is 

 eoncerued with deteiiuining the limits within which each .sjjecies of 

 animal is at the present day contined. Save man, and his faithful 

 attendant the dog, no .species of animal can be said to have anything 

 like a »H(>('/-.vri/ distribution ; and each species, as is a matter of com- 

 mon observation, Ijelongs 1 1 a certain region, and is contined within 

 wider or narrower limits. Thus the Giraffe, for examjile, is not known 

 to exist out of Afi'ica ; the Kangaroos belong to Australia ; the Arma- 

 dillos ilo not occur out of South America, — and so on. Further than 

 this, it is possilile to divide the earth's surface into a certain number 

 of geographical regions or " iiiiihwiinil prorlni:es" each of which is 

 characterised Ijy the occurrence in it of certain associated forms of 

 animal life. Under the head, therefore, of " distribution in space," 

 come two ilirt'erent but allied branches of imjuiry. Fir.stly, we have 

 to iiKpiiie as to the geographical range enjoyed by each individual 

 Rpericx of animal; and secondly, we have to determine what gencnil 

 iixseiii''/'ii/es of animals characterise certain hirge areas or ]n'ovinces, 

 and this alone demaiuls a brief consideration here. 



Tile geograjihical distribution of land animals is conditioned partly 

 by the existence of suitable surroundings, and jiartly bv the presence 

 of barriers preventing migrations. Thus, certain contiguous regions 

 might be equally suitable for the existence <if tlie same animals, but 

 they might belong to different zoological provinces if separated by 

 any iinpassable barrier, such as a lofty chain of mountains. Owing 

 to tlicir power of flight, the geoLjm|ihic,'il distribution of birils is nnich 

 less limited than that of jMamma.ls ; and many migratory birds may 



