of the Mammary Organs of the Kangaroo. 65 
to the other, producing a perfect teat in miniature, in the exact 
situation at which it is found in the adult impregnated animal 
(tab. 3. f. 1. a.). 
. I do not mean to infer from this, that pressure upon this part 
constitutes the means employed by nature for the development 
of the teat; but I mention this experiment to prove the possi- 
bility of eversion without necessary laceration of the part. The 
natural process by which this change is effected I have had no 
opportunity of ascertaining; yet in the absence of positive 
proof, the collateral evidence that such a change must take 
place seems to me too strong to admit of doubt. The com- 
plete absence of the third and fourth teats in the young female, 
and the exact correspondence between the situation of the open- 
ings of these canals, and the spot to which these supernumerary 
teats are always found attached, together with the exact minia- 
ture resemblance to those structures, which an artificial develop- 
ment produces; and, above all, the total want of any other 
structures connected with these parts, by which the production 
of the other teats can be in any way accounted for, —these com- 
bined circumstances afford evidence which, even unsupported 
by any other facts, must, I think, be allowed as confirming the 
correctness of my views upon this subject. 
I have lately examined a young Kangaroo, préversed i in the 
Museum of the Royal College of Surgeons, and which had but 
a few days only been received into the pouch (tab. 3. f. 2.). 
On comparing the extremely minute orifice which forms the 
mouth of the animal at this early period, with the teats of adult 
females during the time of suckling (tab. 3. f. 3.), it seems im- 
possible, from the great size of these parts, that their com- 
paratively enormous extremities should be received within so 
small an aperture as that afforded by the minute opening 
between the lips of the young at this early state of its exist- 
VOL. XVI. K ence ; 
