^^ [April, 



for the specimens of fossil fishes loaned to them by permission of the 

 Society, for comparison and description, and returning the same to the 

 Cabinet. 



^pril 25th, 1848. 

 Vice President Morton in the Chair. 



The Committee to whom was referred Dr. Bachman's communica- 

 tions in relation to the generation of the Opossum, and also the letter 

 oC Dr. Middleton Michel, of Charleston, S. C, on the same subject, 

 addressed to the Rev. Dr. Bachman, reported in favour of publication. 



Notes on the Generation of the Virgmian Opossum (^Didelphis Virgiiiiana.^ 



By John Bachman, D. D. 



Under an impression that the following extracts from notes made at intervals 

 during the last few years, may throw some additional light on the natural history 

 of one of the most interesting of American quadrupeds, I communicate them for 

 the information of the Society. 



March 1st, 184G. — Received to day five female opossums, captured last night. 

 One of these had ten young in the pouch; another nine; the third had eleven ; 

 the fourth fourteen, 'i'hey were all very diminutive, and appeared to be nearly 

 the same age — about two or three days. The fifth was a small animal of the 

 preceding autumn, and I was doubtful whether she had been impregnated. 



March 3d. — On the evening of this day, I examined my small female opossum 

 The mammary organs were considerably distended, and I began to suspect that 

 I had erred in my previous conjectures, and concluded to dissect her on the fol- 

 lowing day. 



March 4th. — At 7 o'clock this morning, when prepared to commence my dis- 

 section of the opossum, I discovered three young in the pouch, and supposing 

 that so small a female would produce no additional number, I concluded that 1 

 would spare her life. She was confined in a box in a room wheie I was writing. 

 When I occasionally looked at her I found her lying on her side, her body drawn 

 up in tho shape of a ball ; the vulva appeared to reach the pouch, which was 

 occasionally distended with her paws. At 6 o'clock in the afternoon, as she 

 had appeared very restless for several hours, I was induced to examine her 

 again, when I discovered that she had added four more to her previous number, 

 making her young family now to consist of seven. With no inconsiderable 

 labour, and the exercise of much patience, I removed three of the young from the 

 teat, one of which perished under the proce.=s. The three weighed twelve grains, 

 averaging four grains each. I replaced the two living ones in the pouch; at 9 

 o'clock examined her and found the young again attached to the teats. 



The young were naked, blind, ears protuberances covered by an integument ; 

 mouth closed, with the exception of a very small orifice sufficiently large to receive 

 the small attenuated teat. Tail \ inch in length. 



March li. — Weighed the largest of the young, and found that it had increased 

 to 30 grains. Length of body 1* inch, tail ^ inch. The nostrils were now 

 open. The young were very tenacious of life, as on removing two they remained 



