1895. THE HABITS OF ARCHAiOPTERYX. 247 



so-called " laws " are all-efficient and irrefragable, and that Natural 

 Selection is a mere whim. Because the middle toe happens to be in 

 the position to be of most use to a horse, we are forbidden by such 

 people to believe that any but the middle toe can be of most use to a 

 bird, and are requested to accept the dogma that the biggest digit in 

 the manus of a horse is the homologue of the biggest in the manus of 

 a bird. The utter worthlessness of such laws is apparent without 

 even looking beyond the hind limb of the bird itself, where Nature 

 has set at defiance this particular law. Mr. Leighton's own paper 

 confutes this absurd notion of the efficiency of these " laws," and he 

 contradicts himself most naively in these words : " It is the ulnar 

 phalanges which must bear the stress of the wing ; the fingers on the 

 radial side, having but few small feathers, would be most likely to 

 disappear." (Op. cit., p. 73.) 



Only one really strong and rational objection to my views has 

 come to my notice. It is a very strong one, and was urged in con- 

 versation by Dr. Jaekel, of Berlin, and subsequently by Professor 

 Dames. They urge the principle, well-known among palaeontologists, 

 that in all fossils we must expect the evidence of things below the 

 surface to appear on the surface ; that all the bones of a single 

 specimen usually lie nearly in a single plane. The bones of 

 Avchceoptevyx in the Berlin specimen certainly do all lie almost in a 

 single plane. There is, however, no evidence in that specimen of the 

 existence of the supposed digits IV and V. What I formerly took 

 for a shadow in the photograph is merely a yellow stain on the slab 

 (but not without significance), and the slender digits I, II, and III are 

 not crushed or distorted as if by underlying bones ; the tibial quills, 

 as I have called them, of the right leg do unmistakably show a dis- 

 placement or distortion where they lie over the left knee ; vertebral 

 and ventral ribs lie in juxtaposition, and so even do the ribs of right 

 and left sides. 



This is a really strong objection, and it is the only strong one 

 that has come to my notice. Even this, however, not only ceases to 

 be an objection, but actually comes to support my view when we 

 enquire more closely into it. Many fossils are distorted much as 

 they would be by enormous vertical pressure : they are flattened 

 much as wax models of them would be by being put in a hydraulic 

 press and squeezed. But Avchaopteryx is not so distorted. The skull 

 is not flattened : its cavity was empty, and not either filled with 

 matrix or abolished by the collapse of its walls. The left femur does 

 not lie in the same plane as the right, but so inclined that its head is 

 now deeply embedded in the slab, while that of the right lies well 

 above the general surface of the slab. The digits do not lie all in 

 one plane ; in the right hand the second lies over the third, crossing 

 it without displacement and without deformation. On the other hand, 

 the first metacarpal lies lower than the second, and not above it as it 

 should in the natural position of the parts. The second metacarpal 



