156 MEMOIR ON THE REPRODUCTION OF THE OPOSSUM. 



innervative existence, sustained by a most active gastric and intestinal digestion, in 

 which an enormous liver plays its part as completely as in the largest quadrupeds. 



The author of a very interesting article on the mammalia in the British Cyclopaedia ot 

 Natural History, is under a similar misconception — and Professor Owen himself, who 

 seems never to overlook any thing in his vast domain of scientific observation, appears 

 not to have had opportunities of dissecting the organs of the very young marsupial. 

 These are the considerations which lead me to offer to the society the remarks contained 

 in this paper. 



Perhaps it might be deemed that the two letters of Dr. Benjamin Smith Barton, Profes- 

 sor of Therapeutics and Materia Medica in the University of Pennsylvania, afford 

 sufficient information upon this curious creature. But I think that though the letter to 

 M. Roume, of Paris, contains much pleasing information, and the other communication to 

 Reimarus, of Hamburg, is full of interest, the two letters together do not clear up some 

 points in the case, which are disclosed by my recent opportunity to observe them, 

 — and, moreover, Dr. Barton's pamphlets are rare — so much so, that I could not obtain 

 an opportunity to examine them until procured by the kindness of Dr. Benjamin Horner 

 Coates, who sent me his copies for perusal. 



The Virginia opossum is so very common an animal in the United States, that one is 

 the more surprised at the rarity of its occurrence in the early stages of its pouch life. I 

 have in vain endeavoured, for many years, to procure a specimen of the earliest embryonal 

 form, which, from the difficulty of obtaining it, is fit to be regarded as a zoological gem. 

 I have, on frequent inquiry, found only here and there a person who had seen the young 

 while very small. No one was able to give me information either as to the rutting season, 

 or the duration of gestation — and it is commonly supposed that the young one grows to the 

 teat by a true vascular anastomosis, and that it is indeed formed there in the pouch, ab 

 initio. I have been surprised at the want of curiosity on the subject among the people, and 

 at the total absence of any general opinion concerning the nature of its marsupial life. 

 Many persons living in the country, and who frequently see the animal in the woods and 

 swampy grounds, seem never to have made any inquiries on the subject. Of great num- 

 bers to whom I have spoken, I never have met with more than three individuals who had 

 observed the young under two inches in length; and I presume, that of the twenty millions 

 of souls now in the union, there are but few persons who are acquainted with the habits 

 of the animal as to the season of its reproduction, the term of its uterine gestation, and 

 the nature and duration of its marsupial growth. The animal is looked upon as one of 

 the vermin, and hunted, out of a spirit of detestation or contempt. 



Some fourteen years ago, I bought, at Camden, opposite to Philadelphia, a female with 

 five young ones; each as large as a half grown rat, and still unweaned. I saw them take 

 the teat, and creep on the mother's back and muzzle, and hold on by means of the pre- 

 hensile tail, wrapped round her ear, or round her leg. I kept them several weeks in my 

 garden. 



In February, 18 15, I also procured a female, with two young ones, as large as small 

 kittens, which I sent to M. Flourens, at Paris, where they safely arrived at the Jardin 

 du Roi. 



