OWEN NOTOTHEEIUM. 175 



fig. 5) ; in Diprotodon it is nearly opposite the interspace between 

 the penultimate and last grinders, being of much less extent 

 (i6. fig. 6). 



A close inspection, with the lens, of the photograph of the upper 

 surface of the expanded end of the muzzle, confirms me in the con- 

 clusion that it does not present that character which indicates the 

 attachment of the horn in the Rhinoceros : the irregularity of 

 surface is not so much upon the upper part as upon the sides of the 

 nasal aperture, which sides are at their upper part peculiarly tumid : 

 but these irregular bossy terminations of the bony muzzle are 

 formed, as we are assured by Dr. Macdonald, by the premaxillaries, 

 not by the nasal bones ; and this is an additional ground for reject- 

 ing the idea that the present large extinct marsupial had a nasal 

 horn like the rhinoceros. 



The cavity of the nose '' is divided by a complete bony septum to 

 within one-fourth of the anterior apertiu^e"* in the Kangaroo and 

 common Wombat : since that remark was printed I have described 

 the skull of a rarer species of Wombat, showing some features of 

 resemblance to the Zygomaturiis, not given by the previously -known 

 kinds, and in which the bony nasal septum advances very close to 

 the anterior outlet of the cavity. By this analogy, therefore, rather 

 than by that of the extinct Tichorhine E-hinoceros cited by Mr. 

 Macleay, I should be inclined to illustrate the significancy of the 

 naso-septal feature in the cranial structure of the large Australian 

 fossil. 



I suspect that the swollen, tuberose, antero-lateral borders of 

 the bony nostril (PI. YII. fig. 4), so well shown in the photograph, 

 have relation to some most unusual developments of the naked 

 ■ integument of the muzzle of the Zygomaturixs or Nototherium, 

 superadding an extraordinary feature to its low-set forward-looking 

 eyes, and very broad low cranium. Future evidences of the forms 

 and proportions of the hmbs of this animal will be received with 

 much interest. 



Wholly concurring in Mr. Macleay's conclusions as to the marsupial 

 nature of the fossil in question, I have to state that the British 

 Museum has now received ample evidence that the generic distinction 

 which Mr. M. beheves to exist between that fossil and Diprotodon is 

 not present. In the cranium of the Diprotodon in the Sydney 

 Museum, of which photographs have been transmitted to me by Mr. 

 George Bennett, the number of molar teeth in the upper jaw 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"t. 



* " Osteology of the Marsupialia," loc. cit. p. 391. 

 t Op. cit. ' Report of the British Association,' 1844. 



