Ratio of increase, [63].
Rats, supplanting each other, [76].
——, acclimatisation of, [141].
——, blind in cave, [137].
Rattle-snake, [201].
Reason and instinct, [208].
Recapitulation, general, [459].
Reciprocity of crosses, [258].
Record, geological, imperfect, [279].
Rengger on flies destroying cattle, [72].