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.