AN EARLY HUMAN OVUM 
4G 
The later stages of attachment and of the formation of the placenta 
do not here concern us, but it must be pointed out that our specimen 
establishes a difference, though perhaps it may be one of degree not of 
kind, between the processes involved in the imbedding of the ovum, and 
those which characterise the commencement of placentation. A distinction 
must therefore henceforth be drawn between the initial stages and phases 
of implantation or imbedding and those of attachment or placentation. 
