Faunas, marine, [348].
Fear, instinctive, in birds, [212].
Feet of bird, young molluscs adhering to, [385].
Fertility of hybrids, [249].
—— from slight changes in conditions, [267].
—— of crossed varieties, [268].
Fir-trees destroyed by cattle, [72].
—— ——, pollen of, [203].
Fish, flying, [182].
——, teleostean, sudden appearance of, [305].