APPENDIX. 323 



No. VI. 



NOTES ON THE CHARACTERS OF 



THE SKELETON OF A DUGONG, 



(Halicore Australis,) 



From the North Coast of Australia, indicative of its specific distinctness 

 from the Halicore indicus and Halicore Tabernaculi. 



BY PROFESSOR OWEN, F.R.S. 



To trace out the law of the modification of generic 

 forms should be the chief aim in the comparison of the 

 characters of different species, or what are so called. The 

 differences about to be pointed out in the skull and den- 

 tition of the Dugong from the North Coast of Australia, 

 are equivalent to those which are interpreted as specific 

 distinctions in the Mammalian division of existing zoolo- 

 gical systems. The bones of the Halicore Australis, here 

 described, were transmitted by J. B. Jukes, Esq., from the 

 North Coast of Australia, Endeavour Strait, lat. 22° S. 



The skull of the young Dugong (Halicore indicus), 

 described and figured by Sir E. Home (Philos. Trans. 1821, 

 pi. 20), measures 8 inches 9 lines in length, retains the 

 deciduous tusks, and has rudiments of the permanent 

 tusks, which are 9 lines in length. The first, second and 

 third molar teeth have cut the gum and been worn : the 

 fourth has pushed its rough, rounded, uneven summit 

 through the alveolus, but, apparently, not through the 

 gum: the rudiment of the fifth, which is the last molar 

 tooth in the Indian species, is concealed in its closed 

 alveolus. 



In a more advanced specimen of Halicore indicus, which 



y 2 



