Lect. VIIL] VOYAGE OF A NATURALIST. 193 



type of tlie group is the common Grey or Norway Rat ; 

 lie is one of the skilfullest, and most cunnino- of the 

 group. But the Beaver is the head or chief of the 

 Order, and his praise is in all zoological treatises. He is 

 at the top ; the Guinea-Pig and his huge relative, the 

 Capybara, are at the bottom. This is in conformity 

 with the well-known fact that in the southern world, 

 new or old, neotropical or pal^otropical, are found the 

 most archaic or lowest forms. 



Thus, in that special territory, the neotro^^ical, we 

 have the Tapir, the Opossum, and the Capybara, and his 

 little, and perhaps still more archaic, relative the Guinea- 

 Pig. This is exactly what I have found with regard to 

 the Bird class : if you want Birds that refuse to fit into 

 well-made zoological systems, that is the place to look 

 for them. I have had my eye upon the Guinea-Pig for 

 many a year, and, working at him from time to time, I 

 have always found something to surprise and stimulate 

 me. The very air of the neotropics must have blown 

 Darwinism into Charles Darwin, when he made that 

 immortal Vot/age of a Naturalist; there "nature 

 wantons as in her prime," — there she brings forth out of 

 her treasures thino-s new and old. This feeble-minded 

 neotropical Rodent, the Guinea-Pig, is full of old 

 characters, especially in his skeleton and his skull ; 

 and those who study other parts know that he must 

 be made to take the lowest room in his Order. At pre- 

 sent, neither in the existing Metatheria, nor even the 



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