VIRGINIAN OPOSSUM. 
123 
young on one side, and six on the other, Icindly brought to us by our 
friend James Fisher, we were unable fully to answer this question. 
Our dissections and examinations were witnessed by Professors Moul- 
trie, Hume, Drs. Horlbeck Michel, Porcher and others. 
The Opossum i.s, as far as we are able to judge from the specimens 
examined, a non-placental animal, inasmuch as there could not be de- 
tected the slightest adhesion between the exterior membrane of the foe- 
tus and the internal surface of the mother. The membranes consisted of 
a vitelline sac, filled with ramifications of omphalo-mesenteric vessels, 
there was a slight appearance of an umbilical cord and umbilical ves- 
sels, constituting a true allantois, but no portions of them were attached to 
the uterus. There was no appearance of a placenta. 
The growth of the young Opossum is suprisingly rapid. We weighed 
the largest young one at a week old and found it had increased from 3| 
grains to 30 grains. Length of head and body exclusive of tail. If inch ; 
tail, f inch. The young at this age were very tenacious of life, as on re- 
moving two, they remained alive on the floor without any covering through 
a cool night, in a room containing no fire, and still exhibited a slight 
motion at twelve o’clock on the following day. The teats of the mother after 
the young had been gently drawn off measured an inch in length, having 
been much distended, and appeared to have been drawn into the stomach of 
the young. The pouches of the young females were quite apparent ; they 
used their prehensile tails, which could now be frequently seen entwined 
around the necks of others. At twelve days old the eyes were still closed, 
a few hairs had made their appearance on the moustache ; the orifice of 
the ears were beginning to be developed, and the nails were quite visible 
and sharp. 
When the young are four weeks old, they begin from time to time to 
relax their hold on the teats, and may now be seen with their heads occa- 
sionally out of the pouch. A week later, and they venture to steal occa- 
sionally from their snug retreat in the pouch, and are often seen on the 
mother’s back securing themselves by entwining their tails around hers. 
In this situation she moves from place to place in search of food, carry- 
ing her whole family along with her, to which she is much attached, and in 
whose defence she exhibits a considerable degree of courage, growling at 
any intruder, and ready to use her teeth with great severity on man or 
dog. In traAmlling, it is amusing to see this large family moving about. 
Some of the young, nearly the size of rats, have their tails entwined around 
the legs of the mother, and some around her neck, thus they are dragged 
along. They have a mild and innocent look, and are sleek, and in fine 
condition, and this is the only age in which the word pretty can be ap- 
