Man instances of closely-allied birds inhabiting distinct countries,
of which the young and the females cannot be distinguished, whilst the
adult males differ considerably, and this may be attributed with much
probability to the action of sexual selection.
INDEX. Abbot, C., on the battles of seals.
Abductor of the fifth metatarsal, presence of, in man.
Abercrombie, Dr., on disease of the brain affecting speech.
Abipones, marriage customs of the.
Abortion, prevalence of the practice of.
Abou-Simbel, caves of.
Abramis brama.
Abstraction, power of, in animals.
Acalles, stridulation of.
Acanthodactylus capensis, sexual differences of colour in.
Accentor Modularis.
Acclimatisation, difference of, in different races of men.
Achetidae, stridulation of the; rudimentary stridulating organs in
female.
Acilius sulcatus, elytra of the female.
Acomus, development of spurs in the female of.
Acridiidae, stridulation of the; rudimentary stridulating organs in
female.
Acromio-basilar muscle, and quadrupedal gait.
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