162 A. A. W. HUBRECHT. 
not traversing the petrotympanic; molar and lachrymal very 
generally in contact on anterior rim of orbit; fourth digit of 
the manus the longest of the series.” 
He adds: “Some... are inclined to deny the genetic 
connection of this group, as well as that of the Chiromyoidea 
with the true monkeys, and assign to them a separate and 
independent ordinal rank. ‘This, however, is manifestly 
incorrect.” After a page devoted to internal anatomy and 
placentation, Wortman concludes: ‘‘ It seems by far the 
safest plan to rely largely if not solely upon osteological evi- 
dence for our conclusions respecting the affinities and evolu- 
tion of the various groups of the Mammalia.” And then he 
finishes by brushing aside the objections I have raised to 
connecting Lemures and Primates in one and the same order. 
In once more vindicating the position which I have taken 
up in this question twelve years ago (’96) I may begin with 
remarking that the last citation, however comprehensible the 
idea there developed may seem from a purely paleontological 
point of view, is not justified in this particular case. Rarely 
have differences of such importance concerning internal 
anatomy been established as is the case between the two sub- 
orders of the Lemurs on the one hand—Tarsius, monkeys, 
and man on the other. 
Wortman seems to have grasped these differences only 
partially, and writes: “It is difficult to decide what value is 
to be attached to the placentation in estimating affinities.” 
In the preceding chapters we have repeatedly shown—as had 
been already done by me before Wortman published his 
paper—that itis certainly not only on arguments drawn 
from the placentation that Lemurs and Primates ought 
to be separated, although the placentation as such is, indeed, 
profoundly different in the two cases. But the difference 
between the evolution of the blastocyst, the part played by 
endoderm and mesoderm in coating the inner surface of the 
trophoblast and the way in which the diplotrophoblast is 
vascularised in a greater or lesser degree in the Primates, 
with the permanent retention of what we have called the 
