LECT. L] THE AUSTEALIAN REGION. 7 



hath cleansed" [made pure and beautiful] "that call 

 not thou common." 



Of the Prototheria (first beasts), the lowest, teatless 

 mammals, we have, now, only two types (genera) left. 

 These are both limited, in their range, within the 

 Australian region ; they are, the Ornithorliynchus, and 

 the Echidna. The former is the lower of the two kinds ; 

 but Professor Huxley's conception of the group in its 

 early, and perhaps abundant, existence is, that it was 

 composed of much less specialised forms than those now 

 living. 



Are we to stand like men who cannot find their 

 hands, because Nature and Time have buried nearly 

 all the truly old families of the Mammalia ? If we are 

 unable to frame convenient hypotheses, to be used as 

 intellectual scaffolding to our facts, we are out of our 

 place in attempting biological research. Let us, if such 

 be the case, stand out of the sunshine of fitter and abler 

 men. 



At present, I have only partially worked out the 

 young of one of these kinds, the Ornithorhynchus ; but 

 although tolerably familiar with the structure of the 

 Vertebrata generally, I am at a loss, even in this early 

 stage of research, to see the meaning of many things in 

 that type. 



Here is a beast a primary kind of beast, a Proto- 

 therian whose general structure puts it somewhere on 

 the same level as low reptiles, and old sorts of birds ; but 



