NOTES ON STRUCTURE, ETC., OF ELEPHANT’S PLACENTA. 9 
although in one or two places nuclei have the appearance of 
extending into these walls, yet such cases are equally open 
to other interpretation. (Fig. 11. nd.) 
Cells with deeply staining nuclei can be found on the 
inside of the homogeneous wall of the maternal blood-channel, 
which cells lie flattened up against the wall. It is not 
possible to follow any connecting strands between the cells, 
but the general appearance is that of a much attenuated 
endothelium. In parts especially nearer to the foetal side of 
the organ there can be little doubt of its endothelial 
appearance, but in the deeper parts and in the larger channels 
the matter is more doubtful. (Compare figs. 8 and 13.) 
In places one is almost inclined to suggest that these cells 
are leucocytes flattened up against the homogeneous wall 
(v, figs. 13 and 14). 
The thickness of these walls is very uniform throughout 
the system of loops, but the walls of the wider channels with 
which the loops communicate are thicker; the outer parts 
of these show a less firm consistency, and stain rather 
differently ; they are really intervillous spaces, as explained 
in Section II. 
As to the origin of these walls and endothelium containing 
the maternal blood we can say nothing definite, but we have 
discussed below some of the possibilities, in our reference to 
the microscopic details of Owen’s specimen. The whole of 
this region (B) is composed of foetal vessels and the fibrous 
tissue which carries them, and these maternal blood-channels 
with their endothelium—if such it is—together with a third 
tissue, a syncytial tissue, which everywhere separates the 
foetal and maternal vessels. 
This syncytial layer, fig. 2 (cy), fig. 11 (cy), is a loose 
granular cytoplasm with faintly staining nuclei (7), scat- 
tered at rather wide intervals. 
This syncytial layer at one place appears more closely 
applied to the foetal tissues, at another more closely applied 
to the maternal blood-channels. At almost all points it is 
crowded with brown and yellow pigment granules, so that in 
