382 A. A. W. HUBRECHT. 
and afterwards taught by Ercolani, Balfour, Hertwig, and others, 
viz. that these remnants originally belong to maternal capillaries, 
which have widened out and have become lacune. They will, 
according to our results, have to be regarded as embryonic 
trophoblast cells, the lacunze themselves as trophoblastic 
lacune. 
Kolliker, Langhans, and others regard the lacune in the 
human placenta as free spaces between chorion and maternal 
uterine surface. The chorion becomes more firmly attached 
to the latter in the placentary region, and finally, by the de- 
structive agency of the proliferating embryonic villi, maternal 
blood penetrates into these lacune (KOll., ‘Entwickelungsgesch. 
des Menschen,’ 2e Aufl., p. 376). 
This latter view has more affinity to the interpretation above 
developed than has Turner’s hypothesis. Still, it requires 
modification in this respect, that these lacune are never at the 
outset free spaces that form part of the uterine lumen, as KOl- 
liker and Langhans (who gave the name of “ Placentarraum” 
to this free space) will have it. 
We have seen in the hedgehog that the trophoblastic lacune 
are never anything of the sort. And when wesee that Hertwig, 
after full consideration of all the contending views, finally 
accords his preference to those of Turner, because they permit 
“to look upon the increase of the vascular channels in 
man as the further development of arrangements that are 
already known in lower forms” (I. c., p. 197) ; then we may 
now vindicate the same for our own interpretation, which has 
more especially the hedgehog, in a lesser degree the bat, and 
to some extent the rodents, to support it. 
It deserves very special consideration whether it would not 
be advisable henceforth to restrict the use of the name 
chorion in mammalian embryology to man, and—dependent 
upon future researches—perhaps to the Primates. Ifit should 
prove true—and already it seems to become more and more 
probable, partly on the grounds that were discussed above— 
that the part which the allantois plays in human placentation 
