178 Review of Darwin’s Theory on the Origin of Species, 
may be regarded as such, the same may be extended to the ter 
tiary period. In both cases, what some call species others call 
varieties; and in the later tertiary shells this difference in judg: 
ment affects almost half of the species ! 
We pass to a second difficulty in the way of Mr, Darwin’ 
theory; to a case where we are perhaps entitled to demand of 
him evidence of gradation like that which connects the present 
with the tertiary mollusea. Wide, very wide is the gap, ana 
tomically and physiologically (we do not speak of the intellee- 
tual) between the highest quadrumana and man; and compare 
tively recent, if ever, must the line have bifurcated. But where 
is there the slightest evidence of a common progenitor? Per 
haps Mr. Darwin would reply by another question: where are 
the fossil remains of the men who made the flint knives and 
arrow-heads of the Somme valley? 
whereas individuals of the very same blood tend to ba 
Stakrak this tendency, and wi 
i -breeds bet 
_ Yersed, and the mongrel is sterile, either absolutely or pe 
He who explains the genesis of species through purely 
for the p epee a ratchet to prevent severe ae 
ane joes 
x dere let us suggest a possibly attainable test of the be fully 
erivation, a kind of instance which Mr. Darwin pole at 1007 
asked to. uce,—viz., an instance of two varieties, OF W""” 
