of the Mammary Organs of the Kangaroo. 461 
The different degrees of development met with in the mam- 
mary organs of the two animals have been since fnn explain- 
ed to me in the following way. 
‘Where a number of female kangaroos have been confined in 
the same inclosure, and have borne in their pouches their 
respective young of nearly the same age and size, —under such 
circumstances it has now and then happened that two of the 
little ones, having escaped from their pouches, have formed an 
association and returned to the common pouch of one or other 
of the mothers ; the animal therefore which is thus destined to 
carry double, must of course be called upon to furnish a double 
supply of nutriment for the tenants of her pouch: it appears to 
me, then, that whenever such is the case, the additional supply 
is afforded by a sympathetic and increased action of the vessels 
of the opposite mamma, in consequence of which a correspond- 
ing secretion of milk is produced, and of course an equal en- 
largement of the mamme and teats on both sides. "That such 
might have been the cause which gave rise to the development 
of two mammz and teats in the kangaroo which I had formerly 
examined, is rendered probable from the circumstance of her 
having been confined in company with others which were also 
bearing young. Iam unable however to prove the truth of the 
position which I have advanced by other than circumstantial 
evidence and analogical deductions; since I have never had an 
opportunity of examining the pouch of any of these animals 
under the circumstances mentioned. 1 may however remark, 
that I have never met with a single instance in which two teats 
had been — in the same moe: M the eer of a 
single young one. — 
With this brief noide of the esie which I have lately ob- 
deris in the condition of the pouch and its contents, I have 
now to describe the appearances presented on dissection of the 
mammary 
