Pectoral Gland in Apes and Monkeys

Abstract

PROF. OSMAN HILL'S interesting account of the gland on the chest of a male drill¹ reminds me that nearly twenty years ago² I described and figured a somewhat similarly situated gland in two adult male gibbons from Borneo. In these apes, the glandular area superficially is an elongated triangular patch of thickened skin sparsely covered with short hairs, and in one of the specimens with blackish secretion. It is broad above and narrowed below, and extends from the region of the inner ends of the collar-bones down-wards and terminates in a point a little below the mammæ. Although I had one of these gibbons under observation in the Zoological Gardens at Regent's Park, London, neither I nor the keeper in charge ever saw the animal evince the least sign of being aware of the existence of the gland; but Prof. Hill's amusing description of the conduct of the drill in connexion with its pectoral gland shows that there is still a great deal of interesting information about the behaviour of wild animals to be learnt by observing them in captivity.