244 THE HISTORY OF CREATION, 



directly allied to the Semi-apes, or Prosimia, among Placental 

 animals. It is possible that these latter are really next 

 akin to the marsupials with hands, and that they have 

 developed out of their long since extinct ancestors. 



It is very difficult to discover the genealogy of Marsupials, 

 and this more especially because we are but very imperfectly 

 acquainted with the whole sub-class ; and the Marsupials of 

 the present day are evidently only the last remnants of a 

 group that was at one time rich in forms. It is possible 

 that Marsupials with hands, those with snouts, as well as 

 rapacious Marsupials, developed as three diverging branches 

 out of the common primary group of Primseval Marsupials. 

 In a similar manner, on the other hand, the rodent, leaping, 

 and hoofed Marsupials have perhaps arisen as three diverging 

 branches out of the common herbivorous primary group, 

 that is, out of the Climbing Marsvipials. Climbing and 

 Primaeval Marsupials might, however, be two diverging 

 branches of the common primary forms of aU Marsupials, 

 that is, of the Primary Marsupials (Prodidelphia), which 

 originated during the older secondary period out of Cloacal 

 animals. 



The third and last sub-class of mammals comprises the 

 Placental animals, or Placentals (Monodelphia, or Placen- 

 talia). It is by far the most important, comprehensive, and 

 most perfect of the three sub-classes ; for the class includes 

 all the known mammalia, with the exception of Marsupials 

 and Beaked animals. Man also belongs to this sub-class, 

 and has developed out of its lower members. 



Placental animals, as their name indicates, are distin- 

 guished from all other mammals, more especially by the 

 formation of a so called placenta. This is a very peculiar 



