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XXIII. On the Fossil Mammals of Australia. — Part III. Diprotodon australis, Owen. 
By Professor Owen, F.B.S. & c . 
Received December 10, 1869, — Read February 3, 1870. 
§ 1. Introduction. — In a letter dated May 8th, 1838, addressed to Sir Thomas Mitchell, 
F.G.S., Surveyor-General of Australia, giving- results of an examination of a series of 
Fossil Remains from caves in ‘Wellington Valley,’ and published in his ‘Three Expe- 
ditions into the Interior of Eastern Australia,’ vol. ii. 8vo, 1838, one of the specimens 
was described as follows : — 
“ Genus Diprotodon. I apply this name to the genus of Mammalia , represented by 
the anterior extremity of the right ramus, lower jaw, with a single large procumbent 
incisor (IX.), fig. 1, pi. 31. This is the specimen conjectured to have belonged to the 
Dugong, but the incisor resembles the corresponding tooth of the Wombat in its ena- 
melled structure and position (see fig. 2, pi. 31, and a section of the Wombat’s teeth in 
fig. 7, pi. 30). It differs, however, in the quadrilateral figure of its transverse section, 
in which it corresponds with the inferior incisors of the Hippopotamus. To this Dipro- 
todon , or to some distinct species of equal size, have belonged the fragments of bones of 
extremities marked X, X a, X b” (p. 362). 
I reproduce the original figures ( W oodcut, figs. 1 & 1 a) representing the specimen of 
half the natural size, and the section of the Kg. ]. 
incisor of the full size, on which the genus was 
founded ; but which specimen I now know to 
be that of a young individual. 
Extraordinary as seemed the magnitude of 
the beast which this tooth indicated, at a 
period when the largest known mammal of 
Australia was a Kangaroo, it gave only half the 
size of the full-grown Diprotodon australis. 
In ignorance of this fact I was led astray 
by the first evidences (femur and molar teeth) la 
of the mature animal which were transmitted to me from freshwater deposits in another 
and remote locality of Australia ; and, for a short time, I believed them to belong to a 
Proboscidian, referring them, in 1843, on the authority of a drawing of part of a jaw 
and teeth transmitted to me by Sir Thomas Mitchell, to the Dinotherian section of 
that order*. 
* Annals and Magazine of Natural History, No. 71, for May 1843. 
MDCCCLXX. 4 B 
