XXII. On the mammary glands of the Ornithorhynchus paradoxus

Abstract

The extraordinary nature of the monotrematous quadrupeds of Australia cannot be illustrated more forcibly than by observing that it is still doubtful to what class of animals they properly belong. In the confines of the animal kingdom, it is less surprising that a species should occasionally be discovered, either so devoid of external character, or of a form so strange, as to occasion a difficulty in ascertaining its class; and an Entozoon, a Lernsea, or an aggregate species of Salpa may require very minute investigation in order to determine its relation even to the most comprehensive division of a methodical arrangement. But the same difficulty occurring with respect to a hairy quadruped, affords one of the most unexpected, as well as interesting problems in natural history, and renders acceptable the smallest addition to the series of facts already ascertained respecting so anomalous a creature.