ARTICLE VIII 



Memoir on the Reproduction of the Opossum. Didclphis Virginiana. By Ch. D. Meigs, M.J). 



Read March 19, 1847. 



Notwithstanding Professor Owen has thrown so much light upon the gestation of the 

 marsupiata, by his publication as to that process in the kangaroo, (macropus major,) I hope 

 a few additional observations that I have had an opportunity to make may be considered 

 as an acceptable contribution to that curious point of natural history and physiology. 



It appears to me that both M. Milne Edwards, in his Elemcns de Zoologie, and M. Pou- 

 chet, in his Zoologie Classu/ue, continue under great misapprehensions as to the state of 

 the very early marsupial embryo; if, indeed, it deserves any longer to be considered as 

 an embrvo, or even as a foetus: terms which cannot, physiologically speaking, be right- 

 fully applied to a mammiferous quadruped, enjoying in full force all the attributes of a 

 warm-blooded and respiratory existence. 



M. Milne Edwards, at p. 2G5 of his volume on the mammiferes, after mentioning the 

 peculiarities of the urethro-sexual canal and wombs, in the marsupials, adds: "Cette dis- 

 position entraine des anomalies extreme dans le mode de reproduction des marsupiauv: 

 les petits ne se developpent pas comme d'ordinaire, dans la poche uterine, mais sont 

 promptement expulses au dehors, et naissent dans un etat d'imperfection telle qu' on ne 

 peut les comparer qu' des embryons a peine ebauches. Ce sont des petits corps gela- 

 tineux, informes et incapables de mouvement, dont les divers organes ne sont pas encore 

 <i i~t incts, et dont l'existence serait impossible si la nature n'avait assure leur conservation 

 par des moyens particuliers." 



M. Pouchet, at p. 262 of the Zoologie Classique, Tome I., says, "Le produit de la 

 generation qui en arrivant la {the pouch,) n'est qu' un simple ovule encore baignl <le fluides 



albumincux, se trouve pose sur les t6tines lis ne prenncnt aloM de nouriture 



que par la bouche sans jamais ainsi que 1' a £mis de Blainvillc, etre en rapport aver la 

 mere au moyen d'un ombilic." 



I propose to show that M. Edwards and M. Pouchet are both mistaken in their views 

 as to the state of the marsupial young, and that, instead of being little "corps gefatineux, 

 informes et incapables de mouvements," or in the state of a "simple ovule encore baignt 

 de fluides albumincux," it is in the full enjoyment of a powerful respiratory, circulating, 



