Je^k, 



Gambicr Dolto" 



BENNETT'S WAI.I.AUY. 



CHAPTER XXXVI. 



The Pouched Mammals, or Marsupials. 



Order Marsupialia. 



Distinctive The whole of the Mammals treated of in the preceding chapters 

 Characters. are collectively characterised by certain peculiarities connected with 

 the development of their young. In all of them the young are brought into the 

 world in a more or less high state of development ; this high grade of development 

 being due to the circumstance that during the greater portion of intra-uterine life the 

 circulatory system of the foetus is connected with that of the maternal parent by a 

 special vascular organ termed the placenta ; this placental connection between 

 the blood-vessels of the parent and offspring allowing the blood of the latter to be 

 oxygenated almost as completely as by breathing. On account of the development 

 of this placenta, the whole of the foregoing orders of Mammals are brigaded 

 together into a single large group, or subclass, and are collectively termed either 

 Placental, or Eutherian Mammals ; the latter term referring to their general high 

 degree of development, as compared with those remaining for consideration. 



On the other hand, in the Mammals of which we have to treat in the present 

 chapter, the young are born at a very early stage of development, and in an 

 exceedingly imperfect and helpless condition, — being, in fact, little more than 



