Chapter 1683
[←1676]
These placentalia of the third sub-class are divided, it appears, into villiplacentalia (placenta composed of many separate scattered tufts), the zonoplacentalia (girdle-shaped placenta), and the discoplacentalia (or discoid). Hæckel sees in the marsupialia didelphia, one of the connecting links genealogically between man and the moneron!!