66 Mr. Morgan's Description 



ence ; but this aperture, minute as it appeared, exactly cor- 

 responded with the extremity of the teat I have before re- 

 ferred to as having been artificially everted ; and further ex- 

 aminations of various living Kangaroos, at different periods of 

 gestation, furnished proof that it is to this lower elongated 

 teat, and not to either of the upper nipples (which were found 

 perfectly developed in the pouch of the unimpregnated Kan- 

 garoo), that the young are invariably attached ; and from the 

 period the young are first received into the pouch, to the time 

 at which they become separated from the teat, the two supe- 

 rior nipples, and the smaller mammary glands attached to them, 

 perform no functions which can apparently be connected with 

 the process of preparing a nutritious fluid for their support. 

 It is also found, that the size and condition of the true teat 

 are constantly changing, in proportion to the growth of the 

 young to which it gives attachment; that as the young ani- 

 mal increases in size, the teat enlarges ; and this structure, 

 — which in the unimpregnated state will measure barely half 

 an inch, and which at the time the young is first attached to 

 it does not exceed the size of that which I had artificially 

 everted, — before the young has left the pouch, becomes en- 

 larged and elongated to the extent of nearly six inches. The 

 upper teats, however, remain in nearly the same condition as 

 regards their relative size and form throughout every period 

 of gestation. 



Repeated recent examinations of the living animal have also 

 proved, that the lower teats, which for distinction 1 may term 

 marsupial, invariably diminish, when the young animal has 

 ceased to suckle, to a smaller size than even that which I had 

 artificially produced by eversion ; but that, after being once 

 developed by protrusion from their original situation in the 

 substance of the gland, they never again recede to their former 



condition. 



