Principle in Palceontologyi 177 



fig. 2, hj and PI. XII. fig. 1, A) are not cemented close together ; 

 on the contrary, their attachment is remarkably weak ; and 

 the symphysis of the mandibles is not firm and compact like 

 that of a koala or a wombat. We find plenty of wombat- 

 jaws in a fossil state with both incisors present ; even perfect 

 jaws are "not uncommon ; and wombat-jaws, as a rule, seldom 

 part at the symphysis : but not a single Thylacoleo jaw 

 has ever been found under such conditions. The wombat 

 is the only marsupial animal which in compactness, shape, 

 and biting-power can at all be compared with our " lionized 

 friend;" and the "formidable carnivore" was only as large 

 again as a common wombat. We know fossil wombats con- 

 siderably larger than the Thylacoleo ; and having experienced 

 the impressions of the teeth of some recent ones, I make con- 

 fession that they bruised the part nipped considerably, but 

 did not draAV much blood ; they crush, but do not tear. The 

 koala bites sharper, and resembles the Thylacoleo more ; but, 

 like the wombat and unlike the '' marsupial lion," it has much 

 firmer jaws, and, were it as large as the Thylacoleo^ would be 

 more formidable. The average form of a koala's lower incisors 

 differs considerably from the hlimt specimens specially selected 

 by Professor Owen, probably for other than Australian readers, 

 and figured on page 233, no. 6, of his treatise. The real car- 

 nivorous marsupials have always a series of small incisor teeth 

 inserted between the canines, which resemble those of ordinary 

 placental carnivores. The most formidable, the Thylacine, or 

 Tasmanian tiger, and the black Dasyure, were numerous in 

 Postpliocene times ; and that they did their duty well in 

 checking the increase of the great herbivores (which were 

 " calves " at some time of their existence) is evident enough 

 from the marks which their strong teeth left on some of the 

 fossil bones. Animals with Thylacoleo-Aexiiiiiow could not 

 make such impressions. 



If dingoes find no difficulty in destroying cattle, the great 

 Dasyures were as able to overpower Diprotodons of respectable 

 size ; so that the Thylacoleo was not required for that purpose. 

 But I am not going to speculate. 



The general form of the lower jaw of our marsupial friend 

 is undoubtedly that of a phalanger. The flattened and but 

 partly enamelled lower incisors are exactly represented by the 

 incisors oi Belidceus and Dactylopsila (PI. XI. fig. 7), even to 

 their serrated edges ; the diminutive canine and one or two 

 premolars are the old story of the phalanger dentition over 

 again ; and the great third " carnassial " premolar (PI. XI. 

 fig. 1, c, fig. 2, and PL XII. fig. l,j) resembles, as in the upper 

 jaw, the outwardly produced formidable tooth of the common 



