260 
PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
Diprotodon, Thylacinus, and Sarcophilus ,” also of what he terms the “ upper incisor and 
lower incisor of Felis tigris, .... showing the relative size of the teeth in these animals, 
and proving sufficiently that the Thylacoleo was far inferior in strength to a modern 
Tiger, and no match for ponderous Diprotodonts and Nototheriums”*. 
If the carnassial tooth were selected instead of an incisor, it would show on the above 
basis that Thylacoleo was “ far superior in strength and carnivority to the modern Tigers 
and Lions.” But I would submit that the test of relative size of a single tooth, if even 
the answerable or homologous one were recognized by the tester, is not a decisive or 
sufficient one in the present question. 
It is evident that Mr. Krefft’s figures 7 & 8 are sections of the canine, not the 
incisor, of the Tiger. But if that tooth in the Hippopotamus were exemplified by a 
similar section, it would be no element, or a very deceptive one, in concluding as to 
strength or carnivority. The canines of Moschus and other like instances will at once 
suggest themselves to the competent Comparative Anatomist. 
To the assertion of the “ gigantic herbivorous Nototherium ” &c. being “ many times 
as large as the Thylacoleo ”f, I will oppose a few matters of fact and mensuration. The 
length of the skull of the largest species of Nototherium ( N . Mitchelli ) is 1 foot 6 inches 
that of the skull of Thylacoleo carnifex is 10 inches 8 lines: were the occipital ridge and 
spine entire in the specimen measured (Plate XIV.) it might be set down at 11 inches. 
It wilTbe within the bounds of accuracy to say that the Notothere was twice as large as 
the Thylacoleo, not more. The skull of the Diprotodon is 3 feet in length ; it is, how- 
ever, large in proportion to the trunk and limbs ; bulk for bulk, it was probably not 
much larger in comparison with the Thylacoleo than is the Giraffe in proportion to its 
destroyer the Lion. The disproportion between the Wolverene ( Gulo luscus) and its 
prey the Beindeer must be greater than that which the dimensions of the known fossils 
of Thylacoleo and Diprotodon suggest. The length of a Lion’s skull before me is 1 foot ; 
that of the skull of a South- African Giraffe is 2 feet 2 inches. If we next compare, not 
a single tooth merely, but the whole lethal tooth-weapons of Thylacoleo and Felis tigris, 
we get the following results. The length from the fore part of the laniary to the hind 
part of the carnassial, upper jaw, is in Felis tigris 3 inches 7 lines; in Felis spelcea 
4 inches ; in Thylacoleo carnifex 4 inches 3 lines. In the lower jaw the proportions are 
reversed ; but the difference affords no reasonable ground for inferring such inferiority 
of strength or destructive power as to support the inference that Thylacoleo was inca- 
pable of playing the same part in relation to the Nototheres and Diprotodons as the Lion 
now performs in relation to the Buffaloes and Giraffes. 
* “ On the Dentition of Thylacoleo carnifex (Ow.),” in Annals and Magazine of Natural History, Third 
Series, vol. xviii. 1866, p. 148. 
t Professor Flowek, F.R.S., however, adopts the argument from size, and rejects the hypothesis “ that Thy- 
lacoleo was the destroyer of the gigantic herbivorous Marsupials (many times as large as itself) with which its 
remains are found associated, the Diprotodons and Nototheres.” — XII. p. 318. 
± Owen, “ On some Outline- drawings and Photographs of the Skull of Nototherium ,” Quarterly Journal of 
the Geological Society of London, vol. xv. p. 173, pi. vii. (1858). 
