Great Books of the Western World: Darwin

adapted affinities America ancient appear beak become bees believe belonging birds breeds cause cells characters cies climate closely allied colour common continent crossed crustaceans degree developed difficulty distinct species doubt eggs embryo existing extinct extremely fact favourable female fertilised fertility flowers formation forms fossil Fritz Müller Gärtner genera genus geological geological period gradations greater number habits Hence hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing intermediate intervals kind lamellæ larvæ less living male mammæ mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occur offspring organisation organs parent peculiar perfect pigeon pistil pollen present principle probably produced progenitor quadrupeds races ranked reciprocal crosses relation remarked resemblance rudimentary seeds sexual sexual selection slight South America stamens sterility structure supposed tend theory tion variability variations varieties vary whilst whole widely wings young