REPTILIA. 249 



Sub-class 1. Reptilia nuda. 

 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 distui- 

 guishing 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 occipitaie, constituted by processes from the ex-occipitals, into 

 which the hasi-occipital of Professor R. Owen does not enter as in the 

 Squamnta. 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, bj 

 the Sauroid Lahyrinthodonts) : 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 oi 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 kino-dom 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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