246 NATURAL SCIENCE. April, 



Mr. Pycraft asks (p. 445), Where did my supposed but unseen 

 digits IV and V articulate in Archceoptevyx ? I have answered this 

 already in the preceding pages of this article ; but there is good 

 reason for answering it again. The digits did exist, and their meta- 

 carpals are conspicuous in the London specimen, and they articulated 

 to that large rounded carpal bone which is shown at the distal end of 

 the radius and ulna of the right wing in Fig. 2, p. 116. 



On p. 446 is a logical error of a type which is very widespread. 

 " A very serious objection " to my theory is that the wing of 

 Archaopteryx must have been highly specialised in two directions — 

 " modifications, too, which must have gone on hand in hand, a possi- 

 bility which I can hardly imagine." Now, though the limits of Mr. 

 Pycraft's powers of imagination may interfere with his comprehension 

 of the works of Nature, they do not in the least interfere with Nature 

 in the carrying out of her work. Bats, Pterodactyles, and Mr. 

 Pycraft's pet Opisthocomus are in various ways modified in two like 

 directions. Nay ! Even Mr. Pycraft has himself urged (on p. 359) 

 that very double modification which he was unable, when writing 

 p. 446, even to imagine. Space does not permit me to notice other 

 points in his argument ; but I believe he will find every objection he 

 has raised full}' met and disposed of in the foregoing pages of this 

 article. 



I may perhaps be permitted to congratulate Mr. Pycraft on 

 having succeeded in opposing my views, on which I know he feels 

 very strongly, without having once lapsed into that violence of 

 language which I find it almost impossible to avoid. I hope that my 

 frank criticism of his article may cause him no more pain than his 

 own criticism of my views has caused me. 



Another critic, Mr. Virgil L. Leighton, in no. iii. of " Tufts 

 College Studies," says (p. 71), " That there is developed a fourth 

 digit in the avian manus is beyond question [!] , and the fact that this 

 comes upon the ulnar side of the three permanent fingers is sufficient 

 to invalidate the nomenclature III, IV, and V of Hurst." The 

 " plausibility " of my view is, moreover, founded on ignorance, and 

 " no one without a theory to support would regard it [i.e., what I 

 called os pisiforme in Nat. Sci., vol. iii., p. 279] other than a digit." 

 Mr. Leighton, of course, knows that greater men than myself regard 

 the os pisiforme itself as the remnant of a digit ; but even if he did not, 

 the alleged resemblance of it to a digit in a certain stage in the 

 development of a certain bird (Sterna) would not in the least affect 

 my conclusions. It is not difficult to name a few mammals in which 

 things occur much more like digits beyond the normal five than the 

 embryonic rudiment he refers to. (N.B. — Rudiment = beginning, 

 germ, thing as yet undeveloped, " Anlage.") 



He further urges " the LAW of digital reduction advocated by 

 Morse, by which in other groups digit I is first to disappear and 

 then V." To me it is astounding to find people who consider that 



