144 [August 



CORRESPONDENCE 



ANATOMY OF BIRDS 



It is hard to be accused of heresy by one whose orthodox faith has been disturbed by 

 his own misreading of a very good text. Mr Pycraft [Natural Science, vol. x. p. 415) 

 complains of my having described "certain membrane bones, to wit, the maxilla, 

 premaxilla, quadrato-jugal, and jugals, as modifications of the first visceral arch," 

 and that this statement does not tally with the analytical diagram. (Article Skull, 

 Newton's Dictionary of Birds. ) Of course it does not, because that diagram is correct, 

 and because I did not include the premaxilla ,and the maxilla as modifications of the 

 first visceral arch. In my copy of the Dictionary (p. 872, line 5), the words "the 

 right and left maxillae " are separated from what follows by a semicolon, and this alters 

 the meaning of the sentence as much as the proverbial fly's dot in Hebrew texts. In 

 the diagram the premaxilla and the maxilla are treated as visceral arches, just as 

 they should be, but I am so orthodox, or courteous, as to leave to the palato- quadrate - 

 mandibular arch its time-honoured name of first visceral. 



Mr Pycraft would have done better not to mention Mehnert, as all " those who have 

 given the matter their attention " ought to know, that Mehnert's conception of the 

 pectineal process is erroneous, and this process is one of the chief clues to the homologies 

 of the pelvic components. 



Lastly, are not the Saxon terms "greater, middle, and lesser" as good as major, 

 medium, and minor ? And if the minor wingcoverts come too near the edge of the wing 

 they become marginals, which as such, by the way, have been mentioned in the article 

 "Tectrices." 



However, I have no reason to complain of my reviewer. He has let me off kindly, 

 and has drawn a veil over certain real faults which I should find it difficult to explain 

 away. ■ H. Gadow. 



Cambridge, June 2\st, 1897. 



THE OSTRACODERMS OF PROFESSOR COPE 



In reference to Professor Ray Lankester's interesting note (supra, pp. 45-47) on the 

 affinities of the early Palaeozoic organisms termed Ostracodermi by Cope, I regret that 

 no new facts of fundamental importance for the discussion of the problem have been 

 obtained since my brief summary published in Natural Science for October 1892. A re- 

 statement of the basis of Cope's view would thus be merely a repetition of the facts and 

 comparisons contained in the literature of the subject up to that date. I should like, 

 however, to remark that neither Professor Cope nor I have ever placed the Ostracoderms 

 in the Marsipobranchii. In the obituary notice of Cope, I expressly referred to them as 

 ' allies ' of those animals ; and they have always been mentioned as at least a distinct 

 sub-class. The chief difference between the views of Profs. Cope and Lankester 

 seems to be, that the latter considers the unpaired character of the nasal aperture in the 

 Marsipobranchii of fundamental importance, while the former regards it as a secondary 

 specialisation of no notable significance from a phylogenetic standpoint. Prof. Cope 

 believed that at the base of the craniate vertebrata, immediately below the true fishes, 

 there could be recognised a class of organisms destitute both of the lower jaw and of paired 

 limbs. He termed those the Agnatha, and eventually placed among them the two distinct 

 sub-classes of Ostracodermi and Marsipobranchii. It still seems to me that this was a 

 great step in advance towards the true phylogenetic arrangement of the lower vertebrata, 

 and it was this that I ventured to ' acclaim ' in the sentence which led to Prof. 

 Lankester's protest. It is well that we who are accustomed to spend so much time in 

 deciphering the tattered relics of extinct organisms in the rocks should occasionally be 

 checked thus in our tendency to speculation ; but, notwithstanding the imperfection of 

 our materials, it becomes continually clearer as we proceed that Palaeontology alone 

 furnishes the criterion for estimating the relative taxonoinic value of the different 

 morphological characters of any group of organisms that happen to possess hard parts 

 capable of fossilisation. A. Smith WOODWARD. 



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