STRUCTURE AND HABITS OF ARCH^EOPTERYX. 273 



39 : 27-5 = more than 1 1 : 8 and 335 26 which is 103 : 8. Further, 

 the bones are utterly unlike their supposed equivalents in the Berlin 

 slab. They are far stouter, and the longer of the two is exceedingly 

 broad at the base, and therein is well-fitted to resist torsional stress 

 or twist at the joint. In their proximal halves, instead of being 

 slender and almost circular in section, they are stout and bave ridges 

 which, when the two were fitted together, would have prevented their 

 movement one on the other. Whatever they are, they are utterly 

 unlike any bones visible in the Berlin specimen. Their position with 

 reference to the feathers of the wing, in spite of the dislocation of 

 other bones, is just that of the large metacarpals in an ordinary bird's 

 wing ; and the fact that these feathers are still in their normal posi- 

 tion in this wing (the left) justifies the belief that when the animal 

 finally settled down previous to fossilisation those feathers were still 

 bound to those metacarpals by ligament. 



This is proof no. 1 that those two bones are the metacarpals of the 

 digits IV and V. 



(2.) The second proof is a more formidable one. Some hundreds of 

 experiments extending over hundreds and even thousands of years 

 have shown the effect of "selection" upon dogs, horses, sheep, pigs, 

 pigeons, poultry, vines, roses, plums, apples, pears, strawberries, 

 gooseberries, blackberries, pansies, daisies, dahlias, chrysanthemums, 

 etc., etc., and the result is the same in all cases. Selection occurs in 

 Nature (Naudin, Darwin, Wallace), and its effect is the same as in 

 the case of artificial selection (Naudin, Darwin, Wallace, Bates, and 

 others). I do not think it necessary to repeat the proof of this state- 

 ment here : the proof is far too long, too well known, and too widely 

 accepted for me to need to say more about it. 



We may, therefore, take it as proved that the form and dimensions 

 and structure of every bone and feather in Archceopteryx is the out- 

 come of long-continued Natural Selection. The form and structure 

 of the bones of the three digits visible in the Berlin specimen, and 

 of the feathers in the same specimen, show what the conditions of 

 selection have been, and what have been the uses of those several parts. 



The digits I, II, and III are long, slender, and clawed. Each 

 metacarpal and phalanx is concave on the flexor surface. The ends of 

 the bones are curved like pulleys, allowing of free movement at every 



