Classification of Chorio-Allantoic Placenta | Chordate | Zoology
The chorio-allantoic placenta has been classified into various types on the basis of its morphology, arrangement of villi, histology and electron microscopy. A. Morphological Classification of Placenta: On the basis of closeness of foetal and maternal tissues, placentae may be of the following three types: 1. Non-Deciduous Placenta or Semiplacenta: In most mammals, the implantation is superficial, i.e, the blastocyst [...]