of the Mammary Organs of the Kangaroo. 46 1 



The different degrees of development met with in the mam- 

 mary organs of the two animals have been since partly 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 mammae and teats on both sides. That such 

 might have been the cause which gave rise to the development 

 of two mammai 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. I am 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. I may however remark, 

 that I have never met with a single instance in which two teats 

 had been developed in the same animal for the supply of a 

 single young one. 



With this brief notice of the changes which I have lately ob- 

 served in the condition of the pouch and its contents, I have 

 now to describe the appearances presented on dissection of the 



mammary 



