CONCLUSIONS. 175 



fishes, whose intricate gills suggested the name Labyrinth- 

 ici, by which they are known. Fishes with tufted gills are 

 more numerous here than in other seas. The insects and 

 mollusks are no less strongly characterized. Among others 

 is the nautilus, the only living representative of the great 

 family of large, chambered-shells which prevailed so exten- 

 sively over other types, in former geological ages. 



440. The large island of Madagascar has its peculiar 

 fauna, characterized by its makis and its curious rodents. 

 It is also the habitat of the Aya-aya. Polynesia, exclusive of 

 New Holland, furnishes a number of very curious animals, 

 which are not found on the Asiatic continent. Such are the 

 herbivorous bats, and the Galeopithecus or flying Maki. 



SECTION III. 



CONCLUSIONS. 



441. From the survey we have thus made of the distribu- 

 tion of the Animal Kingdom, it follows : 



1st. Each grand division of the globe has animals which 

 are either wholly or for the most part peculiar to it. These 

 groups of animals constitute the faunas of different regions. 



2d. The diversity of faunas is not in proportion to the 

 distance which separates them. Very similar faunas are 

 found at great distances apart ; as, for example, the fauna 

 of Europe and that of the United States, which yet are 

 separated by a wide ocean. Others, on the contrary, differ 

 considerably, though at comparatively short distances ; as 

 the fauna of the East Indies and the Sunda Islands, and that 

 of New Holland ; or the fauna of Labrador and that of 

 New England. 



3d. There is a direct relation between the richness of a 



