Index. 203 



Variation, what characters are liable to, must be ascertained by 



direct experiment, 19 



under nature, how it may probably be explained, 74, et scq. 



, limits of, in the horse, 88 



, how it ought to be submitted to the test of experiment, 93 



Variations according to Darwin not transmitted to the young as 



long as they remained such, 97 



of one stock, all domestic oxen were till lately considered, 40 



Varieties in relation to species, views of Polygenists on, also of 



evolutionists, 5 



, interminable debates on, 6 



, Huxley on, n 



, Wigand's views on, 13 



Vermes, it would not be more easy to extirpate, than higher 



creatures, 122 

 Vogt, a polygenist first, then an evolutionist, 4 



W 



Wallace, his labours simultaneous with Darwin's, 3 



on marine faunas of opposite shores of Central and South 



America, 156 



on tree-frogs in Fiji group, 158 



Wigand of Marburg, virtually an adherent of the old notion of 

 limited variability, 3 



, his views of genera and species, 13 



West Indies. See Indies. 



Wolf, American and Old World forms of, 8 



, jackal, and dog, why supposed by John Hunter to spring 



from one stock, 10 



, what might result from a cross of, in a strain of fox-hounds,. 



72, 73 



, different coloured forms of the North American, 76 



, love for man in the, 134 



Wolf-dogs, hybrid, their alleged sterility under close confine- 

 ment, 29 



