168 
The Opossum is very prolific, bringing forth two and sometimes even 
three litters each year. The female produces young when a year old. 
The first litter remains with the mother about two months, by which 
time a second brood is in the pouch. Both litters remain in the vicinity 
of the mother until autumn, by which time they are old enough to care 
for themselves. The number of young found in the pouch is usually less 
than the number born. Six is the smallest and thirteen the greatest 
number observed by Audubon and Bachman, whereas fifteen were found 
in the uterus of one female. Of course thos? in excess of the number of 
teats must perish, as those first attached seem incapable of losing their 
hold. 
The same authors conclude that the young are licked or shoved into 
the pouch by the mother. The pouch is distended by the jaws at times, 
the female lying on one side, with the body drawn into the shape of a 
ball, so that the parts of the genital passage reach the edge of the marsu- 
pial pouch ; then, as the young appear, they are licked into the pouch. 
Experiments made by Audubon and Bachman indicate that the young 
instinctively find and seize the teat. The young, when taken from the 
uterus and rolled in warm cotton, drew the fibers into the mouth. More- 
over, when six of a brood of ten were removed from the teats, and three 
young of another litter, and double the size, were put back in the pouch, 
they were found the next morning attached to the teats, together with 
two of her own which were returned with them. 
The following abstract by Prof. Owen from Dr. Chas. D. Meigs “On the 
Reproduction of Didelphys virginiana,” in American Philosophical So- 
ciety, April, 1847, I transcribe, as adding to our knowledge, of the peculiar 
mode of reproduction in this species : 
‘¢Dr. Meigs reckons the utero-gestation of a female Didelphys virginiana, which bred 
in captivity, as extending from the 18th February to the 7th March—a period of seven- 
feen days—when she brought forth thirteen young, which were found attached to as — 
many nipples. The mamme began to enlarge four days prior to birth. Ona the 6h of 
March she was observed to lay on her side, with her nose turned inward between her 
legs towards her belly, and took scarcely any notice of the keeper’s hand when intro- 
duced into the box. The transit of the foetuses was probably in preparation or operation 
at this time. The young, observed on the 7th, and which were certainly not in the 
pouch on the 5th, and probably not until the night of the 6th, were naked, of a rose 
tint, each three and a half grains in weight, and eight-tenths of an inc’ in length to the 
end of the tail; adhering strongly to the nipple, sucking actively, and clinging to the 
fur by the unguiculate digits of their fore limbs, which they freely used. One survived 
separation from the nipple one hour and twenty-nine minutes, turned itself over and 
moved round the glass in various directions, respiring by the nostrils twenty-two times 
per minute, and ejecting bubbles of milk from its mouth. The hind limbs were each a 
mere bud, with feeble indications of toes without claws. The tongue is very large—one- 
