180 Darwin, and after Darwin. 
But the whole structure resembles the fin of a fish 
about as nearly as it does the leg of amammal. For 
not only are there six rows 
of bones, instead of five, 
suggestive of the numerous 
rays which characterise the 
fin of a fish; but the struc- 
ture as a whole, having 
been covered over with 
blubber and skin, was 
throughout flexible and 
unjcinted—thus in  func- 
tion, even more than in 
structure, resembling a fin. 
In this respect, also, it 
must have resembled the 
paddle of a whale (see 
Fig. 79); but of course the 
great difference will be 
noted, that the paddle 
of a whale reveals the 
dwindled though still clearly typical bones of a true 
mammalian limb ; so that although in outward form 
and function these two paddles are alike, their inward 
structure clearly shows that while the one testifies to 
the absence of evolution, the other testifies to the 
presence of degeneration. Ifthe paddle of Baptanodon 
had occurred in a whale, or the paddle of a whale had 
occurred in Baptanodon, either fact would in itself have 
been well-nigh destructive of the whole theory of 
evolution. : 
Such. then, is the most generalized as it is the most 
ancient type of vertebrate limb above the class of 
Fic. 79.—Paddle of a Whale. 
