REPTILIA. 249 
Sus-ciass 1. Reprinia NupDA. 
Order 1. Batrachia. 
We have already spoken of the general characteristics of Reptiles as a 
class. It now becomes our duty to refer more particularly to the distin- 
cuishing features of the subdivisions, taking them up in the order of the 
preceding systematic arrangement. Our space will not permit us to treat 
of these interesting animals, beyond giving a brief summary of the families, 
recent and fossil; with more particular reference to such genera and 
species as are noteworthy for special properties or peculiarities, or as being 
conspicuous inhabitants of North America. 
The most striking external character of the Reptilia nuda, or the 
Batrachia, is to be found in the perfectly naked, moist skin. This single 
character, conspicuous at first glance, does not yet express all the points of 
difference ; and indeed, of itself, would be far from justifying us in making 
a distinct class of the Batrachia, as some authors have done, or even 
perhaps a separate order. An important feature is to be found, as already 
mentioned, in the double occipital condyles, one on each side of the 
foramen occipitale, constituted by processes from the ex-occipitals, into 
which the basi-occipital of Professor R. Owen does not enter as in the 
Squamata. The skull is depressed and broad, the face having a great 
development at the expense of the cranium, which, with its inclosed brain, 
is small. It is unnecessary for us, in this general description, to do more 
than present the naked skin (the only exception to which is to be found in 
the Peromeles), and the double condyles (the latter shared, however, by 
the Sauroid Labyrinthodonts) : the other peculiarities, by which the Batra- 
chia differ from the scaled reptiles, will fall with the greater propriety 
under more special heads. 
The Batrachia are appropriately divided into three orders: the first, 
Batrachia urodela, having a distinct tail, with the limbs either four 
(represented by the Salamanders) or two; the Batrachia anoura, with the 
tail wanting, but with four legs, always present in the adults, as in the 
frogs and toads; and the Batrachia peromeles, with very minute scales, 
but without limbs and tail, the anus being situated at the extremity of the 
body, as in the Anoura. Lepidosiren would constitute a fourth order, by 
its introduction into the class of Reptilia, but it has already been referred 
to the class of fishes, and the characters of the species are such as almost to 
place it in either at pleasure. 
There is no order in the animal kingdom more interesting to the 
naturalist and physiologist than the tailed batrachians. This results not 
only from the variety of forms, but the progressive changes which are 
observed from an inferior state to a higher, these changes not restricted to 
the embryonic period of existence, as in most other animals, the rest of the 
Batrachia excepted, but extending over periods sometimes of considerable 
length. The two principal sections are characterized, the one by the 
permanent exhibition of lateral spiracles or holes in the neck, the other by 
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