135 



AUSTRALIAN NATURAL HISTORY. 



By Gerard Krefft^ F.L.S.; &c., 

 Curator and Secretary of the Australian Museum . 



[^Eead before the Royal Society, 5 November, 1873.] 



MAMMALS OF AUSTRALIA AND THEIE CLASSIFICATION. 



Part I. — Ornithodelphia and Didelphia. 



AccoRDHsra to geological evidence, the class Mammalia (animals 

 who develop mammary glands for the nourishment of their young) 

 made their appearance on this earth during the Oolitic period. 



The fossils obtained, a few lower jaws and teeth, were referred 

 to the sub-class Didelphia, comprising at present a single order, 

 the Marsupialia. These are distinguished from the Monodelphia, 

 or Placentalia, by bringing forth their young in a very rudimentary 

 state, nourishing them in a " marsupium," which is either a regular 

 pouch or a simple skinfold, such as our native cats and antechini 

 develop at the time of parturition. The living species are almost 

 entirely confined to Australia, to the neighbouring islands, such 

 as the Solomons, Timor, the Aru Group, to New Gruinea, and to 

 Celebes ; in America a siugle genus still lingers, represented by 

 one northern and about thirty southern species. 



The extinct genera found in l^ngland, in the Stonesfield. slate 

 and Purbeck beds, are of small size, about as large as our Ante- 

 chini or Phascogales, and generally considered to represent the 

 most ancient form of mammalian life hitherto discovered. 



According to the theory of evolution, the Ornitliodelpliia (repre- 

 sented in Australia alone by the order Monotremata, the duck-bill 

 or Ornithorhynchus, and the spiny ant-eater or Echidna) should 

 have made their appearance first, but fossil remains of them have 

 not yet been found except in the post-pleiocene deposits of Wel- 

 lington. Some allowance must be made, however, for the incom- 

 pleteness of our geological or palseontological record, so that 

 during future and more systematic investigation additional 

 evidence may be looked for. 



The discovery of fossil remains in Australia extends over a good 

 many years, bones and teeth of mammals of all kinds have been 

 found and shipped Home in large quantities ; palaeontologists 

 have examined and reported upon them, but owing to a scanty 

 supply of the skeletons of modern niarsupials, the classification 

 of these distinguished men has never been as correct as the 

 owners of the fossils had a right to expect. 



The errors which have been made are indeed numerous and 

 varied, the most harmless of creatures have been represented as 

 " the fellest of the fell," animals with all the true characters of 



