1862.] HUXLEY DIPllOTODON. 423 



In the *' Catalogue of the Fossil Organic Eemains of Mammalia 

 and Aves in the Museum of the Royal College of Surgeons " (1855), 

 Professor Owen has given a fuller description, accompanied by figures, 

 of the previously known remains of Diprotodon australis, and has 

 added an account of some fragments of ribs, scapulae, and limb-bones. 

 No portions of the upper jaw, or of its teeth, are described in these 

 successive communications ; but in the paper " On some outline 

 drawings and photographs of the skull of the Zygomaturus trilohus " 

 (Quart. Journ. Geol. Soc. 1859, p. 168), it is stated of " Zygoma- 

 turus,''^ — " By the dentition of the upper jaw this fossil agrees in that 

 essential character with the genus Di])rotodon " (p. 173) ; and further, 

 at p. 175, " The bony palate appears to have been entire or without 

 any unusually large palatal vacuity, in this respect resembling the 

 same part in Macropus major and Diprotodon ; " and again at p. 175, 

 — '' In the cranium of Diprotodon in the Sydney Museum, of which 

 photographs have been transmitted to me by Mr. George Bennett, the 

 number of molar teeth is reduced to eight, four on each side ; but it 

 is by the loss of the first small molar ; and from the appearance of 

 that molar in Zygomaturus, I conjecture that it would also be shed 

 in an older individual. But there are specimens in both the British 

 Museum and the Hunterian Museum which demonstrate that the 

 Diprotodon has five molar teeth developed on each side of both upper 

 and lower jaws, as stated in my ' Report on the extinct Mammals 

 of Australia.' " 



I may remark, incidentally, that I am unable to find any reference 

 to the upper jaw in the ' E-eport ' here cited. In the passage which 

 immediately precedes that just quoted. Professor Owen says, — "I 

 have to state that the British Museum has now received ample 

 evidence that the generic distinction which Mr. MacLeay believes to 

 exist between that fossil {Zygomaturus) and Diprotodon is not 

 present." 



My valued friend Mr. MacLeay, however, by no means made the 

 mistake here attributed to him, of establishing a new genus un- 

 necessarily. " Zygomaturus " is, without doubt, generically distinct 

 from Diprotodon: indeed, Mr. MacLeay's conclusion is implicitly 

 admitted by Professor Owen in the paper which follows that cited 

 above, and which is chiefly devoted to an attempt to prove the 

 identity of Zygomaturus (MacLeay) with Nototherium (Owen) ; for 

 the latter genus is regarded by Professor Owen as perfectly distinct 

 from Diprotodon. 



In the plate (Plate IX.) which accompanied that communication, 

 the left penultimate upper molar of Diprotodon is figured (fig. 6) ; 

 and the transverse direction of the principal ridges, as contrasted 

 with their oblique direction in Nototherium, is noted. 



I have now, I believe, adverted to aU that has been written 

 regarding the dentition of Diprotodon ; and it will be observed that 

 much remains to be learned respecting the premolar teeth and the 

 dentition of the upper jaw generally. I shall proceed, therefore, to 

 describe, at some length, the fossils noted above as Nos. 1 and 2. 



No. ] (PL XXI. figs. 1, 2, 3). This consists of so much of the right 



