animals themselves ? They appear capable of interpretation only as 
the preparation for a vertebral column and a spinal cord to be after 
wards evolved. . . . But the strongest instance of the kind 
which I know of, except that of the brain of man, is the existence 
of pneumatic bones (that is to say, bones hollowed out for lightness, 
like those of flying birds) among Dinosaurians (see Professor Cope’s 
paper on Mcgadactylus probyzelus, as reported in Nature, vol. i., 
p. 347). The resemblances of the skeleton appear to prove that 
birds must be descended from Dinosaurians. No Dinosaurian had 
the power of flight, yet here is a character useful only to flying 
animals, and interpretable only as a preparation for a power of flight 
to be afterwards evolved.”—(Nature. vol. xxxviii., pp. 411-12.) 
In order to show that Natural Selection has had no part 
in the evolution of a nascent organ, it would be necessary 
to prove that at no transitional stage of the development 
has the organ been of any use to the animal in which it is 
developed. Have we any such instance of a tendency to 
develope in definite lines, so that when the evolution is 
complete, and only then, it is capable of performing a 
useful function ? Of course it would be natural for the 
theologian to interpret such a phenomenon as an indication 
of “purpose” ; and looking at the matter from this point 
of view, Mr. Romanes speaks in no uncertain manner:— 
“To deal with the important question before us (the highly- 
specialised and long-elaborated structures) therefore, we must fasten 
attention exclusively upon incipient variations, or variations as they 
occur de novo in first generations. Now I request any teleologist to 
produce evidence that such incipient variations ever exhibit any 
particular tendency to occur in definite lines—still less in lines 
suggestive of any ultimate ‘ purpose.’ And I make this request 
because it clearly rests with the teleologist to furnish some such 
justification of his belief, that the causative influence of Natural 
Selection is supplemented (either wholly or partly) by some causative 
influence of another and ulterior kind, which is supposed to furnish 
variations only in definite, not to say ‘prophetic’ lines. Yet I make 
this request, well knowing that it cannot be complied with. For, 
notwithstanding the opinions expressed by Asa Gray, Nageli, and 
the others, no one has hitherto been able to point to any instance 
of incipient variations thus tending to occur only in definite lines ; 
while, on the other hand, the success of breeders and horticulturalists 
furnishes overwhelming proof that variations occur in such a number