42. THE STRUCTURE AND LIFE OF BIRDS cuap. 
may develop into very birdlike creatures, and so, that 
birds themselves may have had a reptilian origin. 
In the Secondary or Mesozoic period, there were 
upon the earth Pterodactyls or wing-fingered animals, 
also known by the name of Ornithosaurians or Bird- 
lizards. Some very perfect specimens of these have 
been found in the lithographic-stone at Solenhofen 
in Bavaria. England and America have produced 
pterodactyl bones and almost complete skeletons, 
the latter country some of enormous size, and thanks 
to the labours of great anatomists—among them Pro- 
fessors Huxley and H. G. Seeley and Sir Richard Owen 
—we now understand a great deal about these flying 
reptiles, and can form a fair notion of how they lived. 
On looking at a restoration of one of these ptero- 
dactyls, one’s first thought is, that it is their wings 
which prove them to be nearly related to birds. This 
requires to be closely looked into, and what was said 
above about analogy and homology must be borne in 
mind. The wings of birds and pterodactyls are similar 
in function, but in their structure they are very different. 
They are analogous but not homologous. A bird’s 
wing contains three fingers. The first is very small, 
the second is far the biggest and strongest, and to it the 
third is immovably attached. Dr. Hurst! has tried to 
show from the evidence of the Berlin Archeopteryx 
that these three digits are not the first three, but that 
the two united ones are the fourth and fifth. For this 
view, as far as I can see, no evidence is'to be found in 
the Berlin Archeopteryx or anywhere else. But when 
he maintains that the generally accepted view, that the 
1 Natural Science, October, 1893. 
