148 Mr. H. G. Seeley on Prof. Owen's 
tinued in these passages:— The plumous covering of the 
long-tailed bird of the period [Archwopterya] proves its heemato- 
thermal character, as the want of it shows the long-tailed 
Pterosaur to have been cold-blooded ” (p. 73). “ The constant 
correlative structure with hot-bloodedness is a non-conducting 
covering to the body. We may with certainty infer that 
Archeopteryx was hot-blooded because it had feathers, not 
because it could fly ” (p. 73). Living crocodiles, chelonians, 
lizards, and serpents are more or less perfectly covered with 
bony scutes or horny scales, or, as in the case of some che- 
lonians, with both ; neither of these conditions, nor, indeed, 
any covering is known in Ornithosaurs ; therefore Prof. Owen 
has no reason for inferring from the covering of the body that 
the Pterodactyles were reptiles or that they were cold-blooded. 
Yet even scales might not be conclusive of reptilian character, 
for something analogous to a scaly covering is seen on the 
legs of birds; but to infer that the animals were cold-blooded 
because there is no evidence of their having had feathers, 1s 
plainly an absurdity. Not to mention other cases, our own 
species and whales are instances of warm-blooded animals in 
which the skeleton could show no trace of any non-conducting 
covering to the body, even if it existed ; it therefore seems to 
me that in these matters Prof. Owen's philosophy has no basis 
in fact 
lation to high temperature ; and he adds, p. 80, * By the pae 
erre 
n these passages it appears to me that errors are made of 
two kinds :—first, in considering functions without regard to 
their correlative structures; secondly, in not reasoning from 
structures back to the functions of which they are the evi- 
| 
| 
! 
$ 
| 
i 
| 
i 
| 
