That is to say, he believes that, with the exception of the duckbill and the echidna, the mammalian class as a whole can lay claim to descent from small arboreal forms. This view is, of course, almost entirely based upon palaeontological considerations; and these, in the author's opinion, admit of the conclusion that all modern placental and marsupial mammals are descended from a common ancestral stock, of which the members were small in bodily size.   anvd [Please select]

It is the duckbill or duckmole, and is scientifically known as the _Ornithorhynchus paradoxus_.   anvd [Please select]