These ratios are curious and interesting, since they draw the 
I asmanian wombat nearer to the Tasmanian Xototherium than 
they do to the King Island wombat, which is exactly what might 
be expected it food, climate, and environment generally have been 
the chief factors in the segregation of these species, lint if now 
the same bones are compared proximally, in a similar way, we 
get the following data : 
Humerus of X. mitchelli, ratio of width to length .. 15 to 50 
Ditto X. tasmanicum. ditto ditto. 16 to 56 
Ditto King Island wombat, ditto ditto. 25 to 72 
Ditto Tasmanian dittc^ ditto ditto. 20 to 5^ 
Here, again, the Tasmanian Xototherium approaches our 
specifically distinct wombat more than it does the King Island 
form, and my only regret is that the humerus of the King Island 
Xototherium cannot be included in this list. This great deside¬ 
ratum is impossible, however, since the bone was not in the 
matrix so carefully investigated by Alt*. I\ 11 . Stephenson, to whom 
we owe the discovery of these valuable remains. 
A little reflection upon the above ratios will strengthen the 
conviction as to my correctness in the specific determination of 
Xototherium tasmanicum, since the other three animals are 
accepted as being good and true species upon an authority beyond 
all reasonable doubt. 
t)wen and Lydekkcr both state—and Owen’s figures prove 
—that the humerus of X. mitchelli closely approaches that of the 
modern wombat, except that the deltoid is double and the ento- 
condyle is flatter. It is easy to prove that in the matter of 
muscular ridges and processes the humeri of wombats do not 
show any great variation, and certainly nothing equal to that 
manifested by the type humeri of X. tasmanicum, whose characters 
with regard to deltoid, pectoral, and supinator supply the material 
for the construction of a humerus intermediate between X'. 
mitchelli upon the one hand and the modern wombat upon the 
other. 
Lastly, this Tasmanian humerus, in spite of its great length, 
in which it exceeds the type mitchelli by 67 mm., is so reduced in 
width as to fall below the type to the extent of 49 mm. This 
reduction in width means much less surface for muscular attach¬ 
ment generally, while the areas usually allotted to the attachment 
of pronator radii, flexor carpi radialis, and flexor carpi ulnaris, as 
also extensor carpi radialis, extensor carpi ulnaris, etc., etc., are 
both relatively and actually much smaller than those of the tvpe. 
