6 NOTORYCTES. 



experienced considerable difficulty in the selection of such char- 

 acters as appear to be most suitable for the purpose. Dr. Stirling, 

 in his papers quoted above, though at present the only scientist 

 who has had the opportunity of examining the anatomical charac- 

 ters, offers no suggestion as to the definite place which it should 

 take in the zoological system, and I have therefore endeavored to 

 intercalate it among those forms to which it seems to me to make 

 the nearest approach from a structural point of view. The con- 

 clusion at which I have arrived, after an exhaustive study of 

 Dr. Stirling's pamphlet, is that in this animal we have at last 

 obtained a definite connecting link between the Monotremes and 

 Marsupials. In the present initial state of our knowledge it 

 would, in my judgment, be presumptuous to class Notoryctes 

 among the Monotremes proper, nevertheless several of our leading 

 naturalists incline to the opinion that its affinities are closer to 

 these Mammals than to the Marsupials ; at present, however, I 

 pi'efer to look upon it as an aberrant Polyprotodont. If the 

 former view be correct we have here an adult Monotreme possess- 

 ing fully developed teeth, and it must not be lost sight of that in 

 Ornithorhynchus, as previously mentioned (vide p. 2), teeth are 

 developed in both jaws until the animal is fully one-third grown, 

 though our knowledge of the early life of this latter animal is not 

 sufficient to enable us to decide whether these teeth are functional 

 or otherwise ; it is, however, on this character, and so far as I can 

 determine with the slender means at my disposal, on this character 

 alone, that I base my opinion of its polyprotodont affinities ; the 

 absence of canine teeth, if I am correct in my suggestion that 

 those considered by Dr. Stirling to be canines are respectively 

 the fourth upper and third lower incisors, militates against its 

 position as a typical Polyprotodont, but strengthens its position 

 as a true connecting link between the MONOTREMATA and POLY- 

 PROTODONTIA ; if on the other hand Dr. Stirling has taken the 

 correct view of the nature of the teeth in question, my contention 

 as to the polyprotodont character of Notoryctes is materially 

 strengthened; in any case our knowledge is so limited, and our lack 

 of information as to its milk dentition, if any, so absolute, that it 

 would not be wise to separate it from the polyprotodont Mammals. 

 Further the semirudimentary nature of the pouch, which wholly, 

 or at any rate partially, disappears when not in use, points to a 

 connection on the one hand with Myrmecobius and Phascologale, 

 and on the other hand with the PROTOTHERIA ; Dr. Stirling 

 informs me in literis that a pair of minute mammary elevations are 

 present, situated near the corners of the posteriorly expanded pouch 

 The form of the feet and the character of the horny shield on the 

 snout also ally Notoryctes to Echidna. Putting aside these external 

 characters, we have not far to seek in the skeleton for confir- 

 matory evidence of its affinity to the Monotremes, the considerable 



