INTRODUCTION. 
IX 
the praise of having first broken through the contracted notions which had 
been previously held respecting the Testudinata*. The charm once broken, 
it was found that several other types of form existed, of sufficient importance 
to require distinct generic appellations. For example, Geoffroy gave an ex¬ 
cellent paper'f' on the fluviatile species which have a coriaceous covering, and 
other equally distinct characters, to which he gave the name Trionyx. Schweig- 
ger had already assigned to them in manuscript the name Amy da; and as 
Geoffroy was aware of this fact, from Schweigger’s manuscript having been 
submitted to him before the publication of his own Monograph, it is not easy 
to imagine why he suppressed it, and employed a new one of his own. 
In 1820 Merrem published his “Tentamen Systematis Amphibiorum,” a 
work in which the discoveries of former authors are embodied with consider¬ 
able improvements of his own, both in arrangement and nomenclature. His 
separation of the Batrachia from the Reptilia as a distinct class, is an important 
alteration, in which he is borne out equally by their anatomy and physiology; 
and his arrangement of the Reptilia in orders, though not free from some 
obvious objections, evinces a considerable acquaintance with the subject, and 
no slight degree of originality in his views. The application of ordinal terms, 
founded upon the character of the integument, is ingenious, and has the advan¬ 
tage at least of uniformity and convenience. For the present order he adopts, 
from Oppel, the name Testudinata; a term which I have, upon mature consi¬ 
deration, retained as more advantageous and less liable to objection, than any 
other that has been suggested. The grounds upon which I have made this 
choice, will be stated hereafter. The attempt of \this author to give to every 
species an essential character wholly independent of colour, renders the bulk of 
his work almost useless, excepting for the sake of its very extensive synonymy. 
The Monograph of Schweigger J deserves especial mention, as being much 
more complete than any that had previously appeared, and as having antici¬ 
pated some improvements which have since been made by other authors who 
* Essai d'une Classification naturelle des Reptiles, par A. Brongniart: Paris 1805. See also a Paper by the same author in the 
Bulletin des Sciences par la Soc. Philom. No. 35. 
f Memoire sur les Tortues molles, nouveau Genre sous le Norn de Trionyx, par Geoffroy St. Hilaire : Annales du Museum d'Hist. Nat. 
tom. xiv. p. 15. 
+ Prodromus Monographic Cheloniorum, auctore Schweigger : Konisberger Archiv fur Naturwischenschaft, &c. 1812. 
