CLASSIFICATIONS OF THE AMPHIBIA. 273 



{loc. cit. p. 217), — "the presence of two auricles in the heart 

 of the reptiles douteux now renders applicable to the whole 

 class of reptiles the phrase " cor uniloculare biauritum? and 

 forms an additional argument for retaining as an order of that 

 class, the Amphibia of Latreille." Nevertheless, for several 

 reasons, which are unnecessary to be here given in detail, but 

 more especially on account of the remarkable transformations 

 undergone by so many of these creatures, and of the branchi- 

 al apparatus pertaining to almost all the rest, I do consider 

 myself fully justified in keeping the Amphibia in a class alto- 

 gether apart from the Reptilia. I will therefore limit the 

 class " Amphibia " of Linnaeus, to the last family of the ophi- 

 dians, and to all the batrachians in the fourth order of the 

 third class, — "Reptiles," — according to the Cuvierian system. 

 Hence, the present class, Amphibia, will occupy an interme- 

 diate station between the class Beptilia and the class Pisces; 

 and in order to show better the connecting link in the great 

 chain of this portion of the animal creation, whereby the se- 

 veral kinds of the former approximate to those of the latter, 

 I place the genus Cacilia the first, on account of its great 

 resemblance to some of the ophidians, or serpents, with which 

 indeed many naturalists, besides Cuvier, have classed it. — 

 and I terminate the amphibians by the family Proteidw,— 

 which by their permanent and fully-developed gills so closely 

 approach to fishes ; — and among them, the genus Siredon I 

 station quite the last, because Sir. pisciformis, the Axolotl, 

 is in shape and structure most nearly allied to a fish. 



Division l.— VERTEBRATA. 



Class IV.— AMPHIBIA 



Sub-class I. — MONOPNEUMENA. Respiring singly; either by lungs 

 only, or by gills alone. 



Order I. — Abranchia. Gills wanting. 



Family 1. CceciliadcE. Body lengthened, slender, snake-like. Tail ex- 

 tremely short. Legs none. 

 Genus. — Ccecilia. 



Order II. — Caducibranchia. Gills decaying. 



Family 1. Ranidce. Adult body short, roundish, or oval, broad. Tail 

 wanting. Legs four. Tongue long. Tympanum open. 



Genera. — Rana. Ceratophrys. Hyla. Bufo. Rhinella. Otilopha, 



Might not the Fishes also be clearly arranged in one uniform branchial 

 classification, by the difference of form, structure, position &c. of their gills? 

 Vol. III.— No. 30. n. s. 2 f 



