1848.] 45 



the extensive group of Mammals to which the opossum belongs, that are desti- 

 tute of the pouch, the young in these cases adhering to the teats like those of the 

 Florida rat, &c., exhibiting an approach to species of a different conformation. 



7. The manner in which the young are placed into the pouch and attached to 

 the teati, I have referred to in my observations on the female that brought forth 

 her young in the room where I was sitting, on the 4th March, 1846 (although I 

 was not at the time aware that she was in the act of parturition). She was 

 reclining in the corner of the cage, a little on one side, with her shoulders some- 

 what elevated; her body was much doubled, the vulva nearly reaching the 

 pouch, the latter being occasionally opened by her paws. She was busily em- 

 ployed with her nose and mouth licking, as I thought, her pouch, but which I after- 

 wards ascertained was her young. I came to the conclusion that she shoved 

 them into the pouch, and with her nose or tongue moved them to the vicinity of 

 the teats, where, by an instinct of nature, the teat was drawn into the small 

 orifice of the mouth by suction. I observed subsequently that the well-formed 

 young I extracted from the vagina, which T rolled in warm cotton, was instinc- 

 tively engaged in sucking at the fibres of the cotton, and had succeeded in draw- 

 ing into its mouth a considerable length of thread. I may here remark that on 

 the 21st of February of the present year a female opossum was sent to me late 

 in the evening. She had been much wounded on being captured, and died in con- 

 sequence a few days afterwards. On the morning after I received her I perceived 

 in her pouch seven young ; they had not been attached and were dead ; abortion 

 had taken place, and they had evidently been placed in the pouch by the mother's 

 imcontroUable attachment to her offspring even after they were dead. 



8. The opossum is one of the most prolific of our quadrupeds. I consider the 

 early parts of the three months of March, May and July as the periods when 

 they successively bring forth ; it is even probable that they breed still more fre- 

 quently, as I have observed the young during all the spring and summer months. 

 I find in my notes the following memorandum: «' May, 1830. In searching for 

 insects I was removing with my foot some sticks composing the nest of the Flo- 

 rida rat. I was startled on finding my boot unceremoniously and rudely seized 

 by an animal which I soon ascertained was a female opossum. She had in her 

 pouch five very small young, whilst seven others, about the size of full grown 

 rats, were detected peeping from under the rubbish, and were captured." 



0. An interesting inquiry remains to be answered. Is the opossum a placental 

 or a non-placental animal? If I am to understand by this term, whether the 

 opossum has or has not a placenta, I can readily answer in the negative. In 

 these intricate matters the naturalist should, if possible, see with his own eyes, 

 and speak at all times as feeling himself firm on his own feet. I have had all the 

 opportunities I could have desired of perfectly satisfying my own mind on this 

 subject, but can only state that in all the examinations I have made I could never 

 find the slightest appearance of a placenta, and I do not bslieve that one exists. 



I am, however, far from being equilly satisfied on another point, to which I 

 confess my observations were not directed until it was almost too late to make the 

 necessary investigations. Although I do not believe that a placenta exists, or 

 that there is any attachment of the fcctus to the parietes of the uterus, it does not 

 from hence follow as a necessary consequence that there is no allantois. If an 

 animal has a placenta there is a sure evidence of the pre-existence of an allantois ; 

 but there is in many animals, and especially among the smaller species of Mar- 



