Pruner-Bey, on the occurrence of the supra-condyloid foramen in the humerus of man; on the colour of negro infants.

Prussia, numerical proportion of male and female births in.

Psocus, proportions of the sexes in.

Ptarmigan, monogamous; summer and winter plumage of the; nuptial assemblages of; triple moult of the; protective coloration of.

Puff-birds, colours and nidification of the.

Pugnacity of fine-plumaged male birds.

Pumas, stripes of young.

Puppies learning from cats to clean their faces.

Pycnonotus haemorrhous, pugnacity of the male; display of under-tail coverts by the male.

Pyranga aestiva, male aiding in incubation; male characters in female of.