104 CLASSIFICATION OF AMPHIBIANS. 



(or the sharks_, rays, lampreys, &c.) among the fishes. 

 But a much more hnportant advance to a correct 

 knoAvledge of the group, was made hy Cuvier, not so 

 much in the definition of the greater divisions, as in 

 the valuable details which his anatomical knowledge 

 enabled him to give us in the Regne Animal. He 

 there adopts the primary divisions instituted by M. 

 Brongniart, considering the class of reptiles as com- 

 prehending four leading groups : — 1 . The chelonians or 

 tortoises (^Chelonia), in which the heart has two au- 

 ricles. The body is supported by four short legs, and 

 enveloped by two plates or shields, formed by the ribs 

 and the sternum. — 2. The saurians or lizards (^Sauria), 

 in which the heart has also two auricles ; and the legs 

 are generally four, the body being covered by innu- 

 merable small scales, — 3. The ophidians or serpents 

 ( Ophidid), whose construction is similar to the lizards, 

 but the body is always destitute of feet : — and 4. 

 The batracians, or frogs and salamanders (^Batrachia). 

 In this last division, the heart has but one auricle, and 

 the body is covered by a naked skin. The greater 

 part undergo a metamorphosis, having, when young, 

 the form and the gills of fish, but loosing the first, and 

 breathing by lungs when arrived at maturity. Some, 

 however, never loose their gills, and others have never 

 more than tAvo feet. But it was only in the arrangement 

 of M. de Blainville, one of the greatest anatomists now 

 living, that we find, for the first time, the true Am- 

 phibia separated from the reptiles. He arranges the 

 batracians, or the frogs and salamanders, in a new class, 

 because their organisation, as he justly remarks, assimi- 

 lates them to fish. Subsequently, !M. Latreille has made 

 another system of these animals, where we also find 

 the batracians excluded. More recently, however, 

 MM, Dumeril and Bibron, in their elaborate Erpe- 

 tologie Ge/^era/e *, have attempted to revive the old clas- 

 sification, by bringing in the true Amphibia as part of 



* Erpetologie Generale, ou Hist. Nat. complete des Reptiles. Paris, 1534. 

 Of this valuable work, the most perfect in regard to descriptions hitherto 

 published, four thick jolumes have already appeared. 



