OEDEE OF MAESUPIATA. 



The Marsupials, called also Didelplies in BlainviUe's classification, 

 are characterised by the existence, on the anterior portion of the 

 pelvis, of two long, narrow, articulated, and movable bones, which 

 serve in the females, at least in the majority of the species, to 

 support a pouch, situated below the abdomen, and called the 

 marsupial purse or bag [marstipium, a purse). These bones, which 

 have taken the name of marsupial bones, are not peculiar to the 

 females ; they occur also in the males. The animals which are 

 provided with them constitute, therefore, a very great anomaly 

 among the Mammalia, especially as this modification of the 

 skeleton is connected with a verj' peculiar mode of generation. 



In the Marsupials, in fact, the yomig, when they leave the 

 uterus, are not perfectly formed, as is the case with the rest of the 

 Mammalia ; they are prematurely expelled thence, and attain their 

 full development in the abdominal pouch. Thence two phases in 

 the gestation : the uterine gestation and the marsupial gestation ; 

 the first relatively short, the second much longer. We thus find 

 that these animals have, as we tluxj say, two births : the one coin- 

 ciding -with the arrival of the young one in the jDurse or bag; the 

 other with its departure from this natural cradle, and its contact 

 with the outer world. The duration of the gestation, considered 

 ' in its two elements, varies according to its sjiecies. In the larger 

 Kangaroos the fffitus is introduced into the pouch on or about the 

 thirty-eighth day after fecundation, and it remains there for eight 

 months. 



It is not, as one might suppose, by an internal force — by a 

 more or less energetic muscidar action — that the transfer of the 

 young from the uterus to the marsupial purse is eifected. 



From the experiments of a learned English anatomist. Professor 

 Owen, it appears that the mother herself draws them down, by 



