4.46 Prof. Carl Vogt on 
the fine down in its smallest details. It thus follows that the 
restorations of the animal hitherto attempted are wholly 
erroneous. 
After what we have just set forth, it would be quite super- 
fluous to discuss the question whether Archeopteryx should 
be ranked among Reptiles or among Birds. It is neither one 
nor the other. It forms an intermediate type of the most 
marked kind, and confirms, in a brilliant way, the views of 
Prof. Huxley, who has united Birds and Reptiles, to form of 
them, under the name of Sauropsids, a single great section 
of Vertebrates. Archeopteryz is doubtless one of the most 
important guide-posts on the road followed by the Class of 
Birds in more and more differentiating itself from the Rep- 
tiles, whence it has drawn its origin. Bird in its integument 
and its feet, Archeopteryz is Reptile in all the rest of its 
organization, and its structure can only be understood by 
admitting the evolution of Birds by a progressive develop- 
ment from certain types of Reptiles. The Cretaceous Birds, 
so well described by Prof. Marsh, form a further guide- 
post upon this road, since they still keep their teeth, though 
nearly the whole of their organization has already conformed 
to the type of Birds. 
But it concerns us to discuss a little more precisely the 
halting-places of this progressive evolution, and also to give 
some account of the way in which adaptation for flight has 
acted on different parts of the body. 
Besides the power of flying, Birds are yet distinguished 
from most Reptiles, the Dinosaurs excepted, by their vertical 
position on their hind limbs alone. 
In a paper published some time ago (Westermann’s ‘ I]lus- 
trirte deutsche Monatshefte,’ xlv.), I tried to prove that the 
adaptation of Vertebrates to flight is not necessarily combined 
with their adaption to an upright position, and also that the 
transformation of the hind-limbs, so far as to become the 
sole props of the body in walking, is wholly independent of 
the transformation of the fore-limbs to the end of becoming 
wings. The freeing of the fore-limbs from their function of 
props while at rest or in walking can, in fact, be attained in 
