1893- BIOLOGICAL THEORIES. 277 



Those slender fingers, like the free fingers of the Pterodadyla, or 

 of the recent " flying " phalangers and squirrels, or of Gakopithecus, or 

 like the pollex of a bat, are admirably adapted for climbing in trees. 

 They proclaim ArcJia-opteryx to have been a winged quadruped, and 

 this conclusion receives ample support from the weakness of the 

 vertebral column and of the hind limbs, and from the small size of 

 the pelvis and sacrum. 



In the dissected wing, or in any fairly good figure showing both 

 feathers and bones in the wing of an ordinary bird (i, 2), the ala spuria 

 will be seen to correspond to one or more of these free fingers of 

 ArchcEopteryx. I cannot at present see any way of deciding whether 

 it is a vestige of one, or of two, or of all three of them, and I cannot 

 satisfy myself as to whether certain slender feathers seen to lie upon 

 the primary quills in the plate, and making a considerable angle with 

 them, are really coverts as usually described, or whether they were 

 attached to the free fingers. If they are coverts, as seems probable, 

 their position (lying across the primary quills) may be due to the 

 action of a current of water flowing over the recently dead bird and 

 bringing with it the mud which, being deposited^apparently rather 

 quickly — effected the preservation of the specimen in the perfect 

 state in which it was found. 



Dames (3), in his detailed description of the specimen, states that 

 the primary quills (" 6 to 7 ") were attached to the longest finger (II). 

 If while we look at the photograph we consider what would be the 

 result of such an attachment, it must be obvious that it would be 

 twofold. Firstly, the attachment of such a series of quills would 

 render the fingers perfectly useless for climbing, and secondly, a single 

 flap of that wing would twist the phalanges off" at the joints. In other 

 words, both wing and finger would be rendered useless by such an 

 attachment. 



If Natural Selection has been operating long enough and efficiently 

 enough to determine the evolution of so perfect a series of feathers, 

 it is perfectly certain that that same selection will have led also to 

 the evolution of supports for those feathers as fully fitted to support 

 the feathers as the feathers are fitted for flight ; and even if there 

 had been no indication of those supports on the slab, we need have 

 still had no doubt as to their existence. 



That the views which have gained such wide acceptance should 

 have been possible when Owen (4) 30 years ago recognised and 

 figured the very bones in question, is a striking testimony to the 

 credulity of modern zoologists ! 



We read in any text-book that happens to be at hand that the 

 three digits of a bird's wing answer to the " pollex and second and 

 third digits of the pentadactyle fore-limb." Such a statement, though 

 found in almost all modern books which treat of the subject at all, 

 is in no case, so far as I am aware, supported by any evidence what- 

 ever. I believe the statement originated in a mistranslation of the 



