PROOFS OF EVOLUTION. 
49 
ble. The sponge is an egg-layer. Its eggs bud 
or hatch and grow to adult life. These cases 
among the Protista, which are neither strictly 
animal or vegetable, suggest the beginning of 
differentiation from a common protoplasmic cell. 
Turning to the fossil world, we find, as we 
should expect, innumerable examples of connect¬ 
ing forms. In the later deposits, we find remains 
of toothed birds, having many reptilian character¬ 
istics. Reptiles were then not a fixed type, but 
shaded gradually from fish to bird. The Archae¬ 
opteryx, a fossil rarely found, was a true link 
between the birds and reptiles. 
Certainly, no two kinds of living things are 
more unlike than birds and reptiles, or more 
antagonistic in their natures, mutually preying on 
each other; and yet their relationship is clearly 
established. Psychologically, they have nothing 
in common but hate; and yet the bird is only a 
feathered reptile. Within three years, there was 
found, in the slate deposits of Bavaria, a specimen 
of a reptilian-bird—now preserved in the British 
Museum — which has a long, lizard-like tail of 
twenty joints. Says Professor Vogt, “This is 
neither bird nor reptile, but a decided link between 
the two.” In the later chalk formations many 
