66 
T HE TASMANIAN N AT U R A LIST. 
The symphysis of N. tasmanicum is of much greater extent than 
that of ‘ Mitchelli, 1 being in the proportion of eighty to sixty five. The 
jaws are longer, and slightly wider, with a dental canal proportionately 
farther removed from the tooth line. The tooth line itself instead of 
being longer, as might have been expected, is shorter, in the ratio of 
seventy-seven to ninety-four. In a general way the former specimen seems 
to approach the proportions of the modern wombat more than ‘ N. 
mitchelli’ does. 
In his great work upon the Extinct Animals of Australia, 
Professor Owen details the character of the mandibular symphysis, as 
found in the British Museum specimen, No. 43,088, and remarks 
(Page 260, Loc. Cit.), * The symphysis is in a vertical parallel with the 
back lobe of the third molar (M.I.), but not quite extending to the 
interspace between its socket and that of the fourth molar (M 2).’* 
In N. tasmanicum it reaches to the middle of the next tooth. With the 
exception of one measurement of depth, I refrain from giving such data 
for various parts of the ramus, as the upturning of the alveolar ridges 
make it possible to vary the results. In the modern wombat the 
mandible shows the bony substance surrounding the roots of the incisor 
teeth to be so compressed so as to exactly fit the finger and thumb, 
seeming in fact to have been moulded out of plastic materials, which, 
under the compression, formed two bony ridges raised slightly above the 
floor of the median plane of the symphysis. In the present specimen a 
similar result is noted, the ridges being raised 10 m.m., and arched inwards, 
thus forming with the floor of the diastema, a tube three-fourths 
completed with bone. 
Comparative . measurements. 
N. MITCHELLI 
N. TASMANI¬ 
CUM. 
Length of the symphysis ... ... = 
I30 M.M. 
160 M.M. 
Antero-posterior length of the tooth line = 
r88 „ 
'55 .. * 
Width of mandible anterior to coronoid 
process ... ... ... ... = 
T 94 ,, 
203 ,, 
From back of last molar to entry of dental 
canal ... ... ... ... = 
68 „ 
83 „ 
Thickness of mandible below molar 2 
(Owen) ... 
62 
54 
From * Nototherium victorias’ the mandible of 1 N. tasmanicum * 
differs in the greater width of the coronoid regions ; in the ascending 
* Professor Owen’s figure also agrees exactly with his descriptive note upon the 
extent of the symphysis. 
