180 



Though magnitude may be, in one sense, a measure of force, it by no means neces- 

 sarily implies the application of such force, and consequently is any thing but " an 

 important ingredient" in the question of the carnivority of Mus, Mustela, Fhascogale, 

 and Plagiaulax. 



But whatever bears on the interpretation of the singular dentition of the small " pau- 

 cidentate " marsupial, logically applies to the larger one. 



Mr. Krefft gives drawings of sections of the " lower incisor of Tkylacoleo, Nototherium, 

 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 carnij 'ex is 10 inches 8 lines: were the occipital ridge and 

 spine entire in the specimen measured (Plate X.) it might be set down at 11 inches. 

 I t will be 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, however, 

 large in proportion to the trunk and limbs ; bulk for bulk, the animal 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 Reindeer 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, 



* " On the Dentition of Thylacoleo carnifex (Ow.)," in Annals and Magazine of Natural History, Third 

 Series, vol. xviii. 1866, p. 148. 



t Professor Flower, 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). 



