NOTES ON STRUCTURE, ETC., OF ELEPHANT’S PLACENTA. 29 
plasmodium. In this it resembles far more closely the process 
as it is known to occur in Rodents, Insectivora, Tarsius, 
Primates, etc. 
There is, however, this striking difference. In the Rodents, 
Insectivora, Tarsius, etc., the vascularisation of the tropho- 
blast by the maternal blood occurs before the advent of foetal 
capillaries. Inthe elephant the foetal villi are fully developed 
with their capillaries before any trace of maternal vascularisa- 
tion occurs. 
Tn a recent interesting paper in the ‘ Philosophical Trans- 
actions of the Royal Society,’ by C. W. Andrews, on ‘The 
Evolution of the Elephant,” the writer discusses the probability 
of affinity between the Proboscidea and the Sirenia, and gives 
as one of the points of resemblance the supposed fact that 
the placenta in each group is non-deciduate and zonary. The 
author would seem to have derived this statement from 
Flower and Lyddeker’s ‘ Mammals,” where the statement 
occurs that the elephant’s placenta is non-deciduate and 
zonary, Which is misleading, for the zonary part is incom- 
parably the more important, and is, as Turner and Owen 
asserted, deciduate. 
Turner very clearly emphasises these differences in his 
paper on the placenta of the Dugong. In discussing the 
possibility of affinity between the two groups, he says, “In 
this connection, therefore, it is interesting to observe that, as 
regards its form, the placenta, both in the elephant and the 
dugong, is zonary ; though they differ in this very important 
particular, that in the elephant the zonary placenta is 
deciduate, in the dugong it is almost entirely, if not entirely, 
non-deciduate.” 
There is an interesting point in Turner’s description of the 
dugong’s placenta which suggested the explanation of the 
very large thick villi with broken stems, many of which pass 
obliquely through our region C (fig. 3, fb, fig. 15, V”). 
Turner writes of the dugong (p. 655): “ But my descrip- 
tion has shown that, in addition to the multitude of short 
villi and shallow crypts, the dugong also possessed a small 
