passed between Dr. Xoetling and myself respecting the classifica¬ 
tion of Xototheria, l gather that the learned Doctor doubts the 
value of specific characters impressed upon the humerus of either 
our special Xototherium. or else of such in animals generally; but 
a careful study of the humeri of any sequence of animals—accepted 
as being specifically distinct—will quickly show that the correlated 
modifications of skull and shoulder girdle do most strongly and 
emphatically manifest themselves upon the humeri. In this con¬ 
nection 1 would cite the ease of elephants, living and extinct, 
heading the list with Pak^mastodon and ending with the two 
species of modern elephants. 
HUMERI OF ELEPHAXTS, L 1 VIXG AXD EXTIXCT. 
t. Palseomastodon. Humerus with curved shaft, high swell¬ 
ing deltoid regions, supinator ridge low upon the shaft. 
2. Elepltns Primigenjis. Shaft more symmetrical, deltoid still 
high but less abrupt, supinator ridge ascending higher up the 
shaft.* 
3. E. meridionalis. Deltoid coming down the shaft, supinator 
better defined, and approaching it. 
4 and 5. The humeri of the two modern elephants vary chiefly 
in the deltoid regions, asiaticus being more pronounced, and the 
shaft wider proximally. The humerus of Xototherium tasmanicunx 
departs from that of X. mitchclli in exactly the same way as 
elephns primigenius and E. liieridionalns depart from one another, 
and incidentally from Pakeomastodon. 
Coming to closer quarters, and in defence of my table of 
measurements already published, I herewith append a compara¬ 
tive study of the ratios of the humeri of Xototheria and wombats, 
which, according to Lvdekker, probably diverged from a common 
ancestor: 
In X. mitchclli the humerus has a distal width in 
relation to length in the ratio of . 28 to 50 
In X. tasmanicum the same ratios give . 22 to 58 
In the extinct King Island wombat . 21 to 47 
J11 the Tasmanian wombat . 24 to 57 
* At page 252 of Rrit. Foss. Mam.. Prof. Owen says:—" It manifests 
the specific distinction of the humerus of the mammoth in the relatively 
shorter proportion of the great supinator ridge," thus giving to such 
characters the exact value I claimed for them in the establishment of my 
type humerus. 
