STRUCTURE AND HABITS OF ARCHCEOPTERYX. 285 



to. (N.B. — Rudiment = beginning, germ, thing as yet undeveloped, 

 "Anlage.") 



Only one really strong and rational objection to my views has come 

 to my notice. It was urged in conversation 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 Archceopteryx 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 (see 12, Plate XV.) 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 displacement or distortion where they lie 

 over the left knee ; vertrebral and ventral ribs lie in juxtaposition, and 

 so even do the ribs of right and left sides. 



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 Archceopteryx 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 

 and proximal phalanges lie, not in the same plane as the feathers, but 

 well above that plane. Whatever flattening there might have been it 

 could not have lifted the second digit well above the level of the 

 'proximal ends of the quills it was supposed to have supported. The 

 bones of a dead bird, which has fallen on the bottom of a stream, or 



