NOTES ON STRUCTURE, ETC., OF ELEPHANTS PLACENTA. 21 
On the supposition that these stages which undoubtedly 
occur really represent the earlier phases in the normal de- 
velopment through which the more central region has already 
passed—for the central region resembles in all essential 
features the full-term placenta—we have here all the stages 
showing how the maternal blood gains access to the feetal 
part of the placenta. 
The details of these processes are exemplified as far as we 
can determine them with our limited material by the sections 
drawn for figs. 16-24. Fig. 18 shows a more internally-placed 
area where all trace of cell boundary has disappeared ; the 
mesoblastic portions of the foetal villi (f. v.) stand out clearly, 
and between these the broken-down trophoblastic syncytium. 
Nuclei are perceptible, but are less easily stained. 
In this, we see several clear spaces (m. ch.) apparently 
within the common syncytium or plasmodium formed by this 
breaking down of the trophoblast of adjoining villi. ‘l'hese 
spaces have exactly the appearance of having been produced 
by the bursting in of a stream of fluid containing corpuscles 
and so crushing up the fine reticulum of the plasmodium, 
thereby forming the well defined non-cellular walls so 
characteristic of the full-term maternal channels. 
‘The original nuclei of the trophoblast can be seen as fairly 
large oval highly staining nuclei lying on either side of, but 
usually well away from the newly formed channels. Possibly 
they are less numerous than in the supposed earlier stage, 
but of this we are not sure. ‘lhe nuclei of the corpuscles which 
float in the fluid in these channels are much smaller and are 
more deeply stained. 
Whence are these nuclei? ‘The two alternatives are that 
these corpuscles are derived from certain of the nuclei of the 
plasmodium, dividing and causing a local liquefaction com- 
‘parable to the process described by Hubrecht in the placenta 
of Tarsius spectrum (Hubrecht, 9) or they have had some 
more foreign origin and have been brought into their present 
position in a stream driven along where resistance is least by 
the pressure of the maternal blood behind it. 
