NOTES ON STRUOTURE, ETC., OF ELEPHANT’S PLACENTA. 381 
more prolonged villi, which have been torn off and probably 
left embedded in the walls of the uterus; (d) a few torn ends 
of blood-vessels. 
2. The main trunks of the villi and their foliaceous termi- 
nations are everywhere separated from the maternal blood- 
channels by a syncytial layer, which is continuous with the 
epithelium covering the lobate terminations, and is presumably 
trophoblastic. 
3. The half-term placenta originally examined by Owen in 
1850 shows, in its more central region, characters which are 
essentially similar to those of the full-term specimen, and goes 
far to prove the existence of longer villi which penetrate 
deeply into the uterine mucosa. ‘The lateral areas of the 
zonary belt exhibit many most interesting previous condi- 
tions. We are able to see in these the simple terminations of 
the foetal vilii covered with a single layer of trophoblast sepa- 
rated from the uterine tissues by a layer of material partly 
maternal and partly of foetal origin. 
There is no process of growth round existing maternal 
capillaries to form an angio-plasmode, nor apparently any 
phagocytic action on the part of the trophoblast. The vascu- 
larisation of the after-birth is effected by the invasion of the 
trophoblast by extravasated maternal blood, which flows at 
first in intercellular and intervillous passages which form 
the larger channels of the after-birth maternal vascular 
system, and then makes its way along intra-cellular or intra- 
syncytial canals through a plasmodium produced by the 
breaking down of the trophoblast of two adjoining villi. 
We think the evidence is in favour of considering the 
corpuscles floating in this invading stream, which contains no 
red non-nucleated corpuscles in its more advanced portions, 
to be of maternal rather than trophoblastic origin. | 
4, The tissues of the full-term placenta contain pigment 
granules, which are deposited chiefly in the syncytial layer. 
This we regard as an excretory product; it is almost quite 
absent from the tissues of the half-term specimen. Leuco- 
cytes, either of maternal or foetal origin, seem to be concerned 
