III. 



The Structure and Habits of Archaeopteryx. 



V. — Answers to Critics. 



MANY and various arguments have been urged against my view as 

 to the homology of the digits of the wing of an ordinary bird, as 

 well as against my interpretation of the photograph of Archczoptevyx and 

 other contentions contained in an article on the sources of error 

 (Nat. Sci., vol. iii., p. 275). 



I will take the most frivolous first, and this is undoubtedly contained 

 in a letter signed " A.S.W." Though the text of the German edition of 

 Zittel's " Palaeontologie " is perfectly clear and definite, and describes 

 the fore-limb precisely as it figures it, he nevertheless suggests that 

 it was so figured merely through an almost impossible accident to the 

 block. I do not suppose anybody who has looked at that edition will 

 for one moment hesitate to pronounce A. S. W.'s suggestion to be 

 pure nonsense, and I should not have deigned to reply to it had not 

 the letter contained a suggestion of unfairness on my part. It is not 

 obvious, as A. S. W. states, that the omission of the digit in the figure 

 " was an accident, and not intentional." It is obvious that the digit 

 was omitted in both text and figure intentionally, and that Professor 

 Zittel fully meant what he said, for he argues as to what those three 

 digits were, and draws conclusions as to the relation of Archccopteryx 

 to other animals. Let him who doubts it read p. 822 of the third 

 volume of the book in question for himself and his doubt will vanish. 

 The real omission was not so much omission of a digit as the omission 

 of a note to the effect that Owen's figure had been altered. The 

 omission to note such alterations is a very common one, and I 

 attached no blame to it. I merely asked if it was right. Since no 

 one has answered me, I may now say that I think the custom is most 

 objectionable, and leads, or may lead, to serious error and, as in this 

 case, to the attribution of an error to a person (Owen) who was not 

 responsible for it. 



Mr. Pycraft has devoted quite a large space to some interesting 

 observations on Opisthocomus, but they appear to lend no support to 

 his conclusions as to Archccopteryx. He does not even attempt to 

 show that the digits of Opisthocomus are any but III, IV, and V. 

 Interesting as his communication is, it has absolutely no bearing on 



