320 PALEONTOLOGY. 



the period when most fishes have the flexible and soluble 

 cycloid or ctenoid scales. 



Of the tailless or " anourous " Batrachia, toads of extinct 

 species (Palceophrynos Gessneri and P. dissimilis) have been 

 discovered in the (Eningen beds ; and frogs, more abundantly, 

 in both miocene and pliocene deposits of France and Germany. 

 The batracholites from the tertiary lignites of the " Siebenge- 

 birge," near Bonn, shew different stages of transformation of 

 the Rana diluviana, Gdf. Tertiary shales from Bombay have 

 shewn remains of the small fossil Rana pusilla. 



Of the salamander family, the most noted fossil is that 

 which, from the size of the head and vertebras, was referred, 

 when first discovered at (Eningen in 1726, to the human 

 species, as the Homo diluvii testis. Cuvier demonstrated its 

 near affinities to the water-salamander (Menopoma) of the 

 United states. More recently a living species of salamander 

 has been discovered in Japan which equals in size the fossil 

 in question — Andrias Scheuclizeri. 



A retrospect of the foregoing outline of the palaeontology 

 of the class of reptiles shews that, unlike that of fishes, it is 

 now on the wane ; and that the period when Reptilia flourished 

 under the greatest diversity of forms, with the highest grade 

 of structure, and of the most colossal size, is the mezozoic. 

 The progress of air-breathing vertebrates, graduating by close 

 transitional steps from the water-breathing class, has been 

 checked, as if it had been unequal to the exigencies and life- 

 capacities of the present state of the planet. Eeptiles have 

 been superseded by air-breathers of higher types, which cannot 

 be directly derived from the class of fishes. A more genera- 

 lized vertebrate structure is illustrated, in the extinct reptiles, 

 by the affinities to ganoid fishes shewn by the Ganocephala, 

 Lahjrinthodontia, and IchtTiyopterygia ; by the affinities of the 

 Pterosauria to birds, and by the approximation of the Dino- 



