300 GEOGRAPHICAL ZOOLOGY. [part iv. 



Turdidse, aud the Paridae, are the only otlier families that ap- 

 proach universality of distribution, and all these are want- 

 ing in one or more sub-regions. If, now, we divide the 

 globe into the New and the Old World, the former including 

 the whole American continent, the latter all the rest of the 

 earth, we find that the Old World possesses exclusively 23 

 families, the New World exclusively 14, of which 5 are common 

 to North and South America. But if we take the division 

 proposed by Professor Huxley — a northern world, comprising 

 oiu" first four regions (from Nearctic to Oriental), and a southern 

 world comprising our last two regions (the Australian and 

 Neotropical) — we find that the northern division possesses only 

 5 families exclusively, and the southern division 13 exclusively, 

 of which not one is common to Australia and South America. 

 This plainly indicates that, as far as the Passeres are concerned, 

 the latter bipartite division is not so natural as the former. 

 Again, if we compare temperate with tropical families (not too 

 rigidly, but as regards their general character), we find in the 

 northern hemisphere only two families that have the character 

 of being typically temperate — the Cinclidse, and in a less degree 

 the Ampelidse — both of small extent. In the southern hemi- 

 sphere we have also two, the Phytotomidse, and in a less degree, 

 the Pteroptochidae ; making two wholly and two mainly tem- 

 perate families. Of exclusively tropical families on the otlier 

 hand, we have about 12, and several others that are mainly 

 tropical. 



The several regions do not differ greatly in the number of 

 families found in each. The Nearctic has 19, the Palsearctic 21, 

 the Ethiopian 23, the Oriental 28, the Australian 29, and tlie 

 Neotropical 23. But many of these families are only represented 

 by a few species, or in limited districts ; and if we count only those 

 families which are tolerably well represented, and help to form 

 the ornithological character of the region, the richness of the 

 several tropical regions will appear to be (as it really is) com- 

 paratively much greater. The families that are confined to 

 single regions are not very numerous, except in the case of 

 the Neotropical region, which has 5. Tlie Australian has only 



