576 Fossil Molar Tooth of the Mastodon Ajtslralis. 



ample of a complex molar tooth. In the Australian specimen under 

 consideration the mastodontal characters are unmistakeable, and the 

 resemblance to the molar teeth of the Mastodon angustidens is very 

 close. The specific distinction of the Australian Mastodon rests, 

 at present, only on the slight differences pointed out in the form of 

 the mastoid eminences and the contour of the crown of the molar 

 tooth. 



The question may arise, whether identity of generic characters in 

 the molar teeth of an extinct Australian mammal with those of the 

 Mastodon can support the inference that the remaining organization 

 of the Probosidian Pachyderm co-existed with such a form of tooth. 

 The analogy of the close mutual similarity which exists in the molar 

 teeth of the Tapir, Dinothere, Manatee and Kangaroo suggests the sur- 

 mise that the mastodontal type of molar teeth might also have been 

 repeated in a gigantic Marsupial genus which has now become 

 extinct ; and such an idea naturally arose in my mind after having 

 received evidence of the marsupial character of the Diprotodon and 

 Nototherium*, two extinct Australian genera, with the tapiroid type 

 of molars, represented by species as large as a Rhinoceros. 



The more complex character of the molars of the Mastodon, and 

 the restriction of that character, so far as is now known, to that 

 genus only, makes it much more probable, however, that the molar 

 here described belonged to a true Mastodon, and the species may be 

 provisionally termed Mastodon australis, 



London, August 22, 1844. 



* The characters of these genera, and the evidences of their marsupipal nature, will be the 

 subjects of a future communication. 



