280 C. H, HURST, PH.D. 



the animal walked, or even stood, on two feet at all, it would have had 

 to stand either bolt upright or with its dorsal surface directed slightly 

 downwards. Whether the tail would then be on the ground (as in a 

 kangaroo) or in the air (as in a squirrel) is open to doubt, for we do 

 not know enough about the flexibility of its proximal portion to be 

 able to say with certainty whether it could or could not be bent up 

 over the animal's back. The presence of a long, heavy neck and 

 massive head, which were supported by an elastic ligament, as shown 

 by the curvature of the neck in the fossil (as in Compsognathus and 

 the pterodactyles), add greatly to the force of this argument. A duck 

 has to walk with its body tipped up almost on end, in spite of the 

 great shifting of the heavy organs of the abdomen backwards between 

 the legs. There is no room for doubt that in Archoeopteryx the centre 

 of gravity would be much further forward, not only on account of the 

 heavy head and neck, but also on account of the solidity of the wing- 

 bones, as shown by the absence of pneumatic foramina. Let any who 

 doubt the justice of this argument compare the pelvis as seen in 

 Plate XVI (which the authorities of the British Museum have kindly 

 allowed to be prepared in illustration of this article) with the pelvis of, 

 say, a pigeon or a dinosaur, or any other animal whatever capable of 

 walking on two limbs in any but an erect position. The small size of 

 the cnemial crests, moreover, forbids us to believe that the hind-limbs 

 alone were able to bear the weight of the body when the knee was 

 bent. 



This bird was not only not a biped, but it did not walk on the 

 ground at all. It would have been as helpless on the ground as a bat 

 or even a sloth. The great length of the hind-limbs and shortness of 

 the fore-limbs, at any rate when these latter were so flexed as to keep 

 the feathers off the ground ; the position of the shoulder joint, and 

 especially of the articular surface of the humerus : these render the 

 animal unfit for such a habit as even quadrupedal locomotion on the 

 ground. The perfect state of the wing-quills at their tips shows that 

 they were not brought habitually into contact with the ground, and I 

 know of no rational argument in favour of the view that the animal 

 did live largely upon the ground. For quadrupedal locomotion in 

 trees the animal is admirably adapted. Long, flexible digits, provided 

 with claws on all four limbs, fit it at least as perfectly to arboreal 



