606 CLASS XVII. 



of the pachyderms, the edentates, and the apes belong. The apes 

 indeed, with respect to their distribution, have been compared to 

 the parrots amongst birds; but here this great difference is observ- 

 able, that of the species of apes occurring in the old world, the 

 largest half belongs to Africa, whilst Africa possesses very few 

 species of parrots as compared with Asia. In New Holland also 

 there are no apes, where various species of Psittacus occur. Insecti- 

 vorous mammals, with the exception of the genus Chrysodiloris, 

 are a form almost peculiar to the northern hemisphere ; the Le- 

 murids more to the southern hemisphere. From a more careful 

 comparison a greater number still of such contrasts would be de- 

 duced. The connexion also should not be forgotten which prevails 

 between the distribution of plants and animals; and as in the 

 vegetable kingdom, so also in the animal, of those genera which in 

 cold districts have numerous species, the species occurring in warm 

 countries are found more on mountains than on plains 1 . 



With the exception of some species of bats and of the true whales, 

 mammals are not tied, like birds of passage, to make strictly limited 

 migrations, but inhabit the same districts in winter and summer 

 alike 2 . On the other hand, different species hibernate, and pass a 

 greater or less portion of the year without food in caves and hiding- 

 places. Amongst such in Europe are, for example, the bats, the 

 hedgehog, the hamster, the marmot, and various other species of 

 rodents forming the genus Myoxus, and in the north, the bears. 

 (Just as the same species of birds in cold countries migrate, and in 

 warm countries remain for the whole year, so also the phenomenon 



1 On this subject may be compared J. A. G. ZIMMEBMANN Specimen' Geographice 

 Quadrupedum, L. B. 1777, 4to (antiquated); TREVIRANUS Biologic, 11. s. 174 263, 

 in different places; ILLIGER UeberblicTc der Sdugefkiere nach ihrer Vertheilung uber 

 die Welttheile. Abh. der Konigl. ATcad. der Wissensch. zu Berlin, I. 1815, s. 39 159; 

 WILBRAND und KITGEN Gemdlde der organ. Natur, s. 6988 ; L. K. SCHMARDA Die 

 geograpkiscke Verbreituny der Thiere, Wien, 1853, 8 vo (compiled with great literary 

 knowledge). 



3 It would seem, however, from some observations, that certain species of bats 

 migrate; see GLOGER in OKEN'S Isis, Bd. 21, 1828, s. 1113 1124, BLASIUS Amtlicher 

 Bericht uber die Versammlung zu Braunschweig, 1841, s. 63. The whales, which pass 

 the summer in the polar regions, voyage southwards in winter into the Atlantic Ocean ; 

 some species follow probably the numerous shoals of fishes, for greater abundance of 

 food. Compare ESCHRICHT Untersuchungen uber die nordischen Wallthiere, s. 6 10, 

 and in other places. 



