INTRODUCTION. 
XI 
duced to the rank of a Tribe, and are divided into five families, which were 
adopted, though with considerable improvements, by Mr. Gray. This arrange¬ 
ment differs but little from the quinary distribution which I proposed at nearly 
the same period *, and without any knowledge of the existence of such a work 
as Fitzinger’s. The differences which exist between the method of this author 
and that which I proposed, are almost all in favour of the former; and I have 
adopted the general plan, with the improvements of Mr. Gray, and some sub¬ 
sequent modifications of my own, in the present work. 
In 1830 a work, purporting to present “ a Natural System of the Amphibia If,” 
made its appearance, from the pen of Dr. Wagler. The unnecessary and un¬ 
natural multiplication of genera, founded upon very trifling distinctions, into 
which this author has divided the Testudinata, appears to me to evince a very 
inadequate appreciation of the true importance of characters, and is remarkably 
contrasted with an error of the opposite kind in some other parts of his work; 
whilst the quotations from other authors are in some cases so incorrect as to 
convey an exactly opposite impression to that originally intended^. The 
Plates which illustrate the work, and of which one fasciculus only has yet 
appeared, comprising the Testudinata, are beautifully executed, and exhibit 
not only the external form, but the anatomical characters also, of each genus. 
Passing over those casual additions to our information, which have now and 
then appeared in the description of new species, or the occasional establishment 
of a genus, I proceed, with mingled pleasure and reluctance, to make a few 
observations on a portion of the “Synopsis Reptilium” of Mr. Gray, first pub¬ 
lished as an Appendix to Griffiths’s translation of Cuvier’s “ Regne Animal,” and 
subsequently, with considerable alterations, as a distinct work§. As my ob¬ 
ject at present is not so much to give a critical examination of the different 
authors to whom I may have occasion to allude, as to point out to whom we 
are most indebted for the gradual improvement of our knowledge in this 
* This had remained unpublished for a considerable period, and at length appeared in the Zoological Journal, vol, iii. p. 513. 
f Natiirliches System der Amphibien Sfc. von Dr. Joh. Wagler: Miinchen &c. 1830. 
t See particularly the characters of my genera Kinixys and Pyxis. The essential character of the former, as given in the Linnsean 
Transactions, is, “ Dorsi pars posterior mobilis.” Dr. Wagler gives it, “ Thoracis pars antica mobilis.” This is in fact the character of 
Pyxis, of which this author says, “ Thoracis pars postica mobilis.” 
$ Synopsis Reptilium ; or Short Descriptions of the Species of Reptiles: by John Edward Gray, &c. Part I. 1831. 
