20 



should we not plunge nomenclature if we were to adopt the practice 

 of the learned Professor, instead of the precepts so judiciously laid 

 down by himself and others of the Committee of Nomenclature of the 

 British Association, and which I quote as a justification on my part 

 for my refusal to adopt the learned Professor's exchange of my name 

 for the one he has proposed ! 



In page 4 of the Report, under the head of " Law of Priority the 

 only effectual and just one," we find the following passages :--" It 

 being admitted on all hands that words are only the conventional 

 signs of ideas, it is evident that language can only attain its end 

 effectually by being permanently estabhshed and generally recog- 

 nized. This consideration ought, it would seem, to have checked 

 those who are continually attempting to subvert the established lan- 

 guage by substituting terms of their own coinage." " Now in 



zoology no one person can subsequently claim an authority equal to 

 that possessed by the person who is the first to define a new genus 

 or describe a new species ; and hence it is that the name originally 

 given, even though it be inferior in point of elegance or expressive- 

 ness to those subsequently proposed, ought, as a general principle, to 

 be permanently retained. To this consideration we ought to add the 

 injustice of erasing the name originally selected by the person to whose 

 labours we owe our first knowledge of the object." To these excel- 

 lent principles the learned Professor has given the sanction of his 

 signature. Prof. Owen, in the article on Pteradactyhis in Mr. Dixon's 

 work, has not quoted my observations on those Reptiles so fully as I 

 could have wished ; inasmuch as he has adverted to the strongly- 

 marked peculiarities of the bone-cells, which are the principal cha- 

 racters in the question at issue, in so slight a manner, as almost to 

 induce me to imagine that he must have forgotten them entirely. I 

 shall simply content myself in challenging Prof. Owen to produce 

 any such general structure and proportions of the bone-cells from the 

 skeleton of any recent or extinct bird as those existing in the long bone 

 described as Cimoliornis, or to produce any such radius and ulna of a 

 bird containing similar bone-cells as those in the possession of Mrs. 

 Smith, and figured by me in my paper in the ' Quarterly Journal of 

 the Geological Society for February 1848,' vol. iv. pi. 2. 



On the subject of the strictures with which Prof. Owen has fa- 

 voured me at the conclusion of his observations in Mr. Dixon's work, 

 and how far I have been " wanting in a due comprehension of the 

 subject, and have been a hindrance instead of a furtherance of true 

 knowledge," I am content to leave to the judgement of those who 

 may feel a sufficient degree of interest to induce them to peruse what 

 I have written in my former papers on the Pterodactyles of the Chalk. 



