KESULTS OF PAL.EONTOLOGICAL KESEAKCH 31 



(2) Of the Vertebrates, the Fishes (Silurian) show no 

 connection with lower forms : they appear as suddenly 

 existent. 



' We recognize the Fishes as the oldest Vertebrates, 

 which already in the lower Silurian formation appear 

 as clearly separated from the Invertebrates/ l They 

 are, indeed, not only different from the Invertebrates 

 from the beginning, but in the group of the primary 

 fishes itself '. . . there are numerous quite different 

 types co-existing but separate from the beginning/ 2 

 The same remark applies to the first Amphibia and 

 Kepti ha. 3 It is true that in the Permian system (in 

 the Carboniferous there appear a few representatives) 

 a peculiar group of animals widely prevailed the so- 

 called Stegocephalse which possess many characters 

 of the present Amphibians (free larval condition and 

 two occipital swellings) and others of the present 

 Keptilia (scaly covering) in combination. In their 

 appearance they resemble, for instance, salamanders 

 (Amphibia) or lizards, crocodiles, and snakes (Eeptilia). 



But, contemporaneously, there already lived true 

 reptiles (among them Hatteria up to the present time) 

 and true Amphibia even previously (see p. 28). The 

 Stegocephalae cannot therefore be regarded as the 

 common ancestors of the Reptilia and Amphibia. 



With regard to the origin of the present reptilian 



1 Steinmann : Die Geologischen Grundlagen der Abstammungslehre, p. 203. 



2 Ibid. p. 206. 



3 Ibid. The origin of the Quadrupeds is still not cleared up. Koken : 

 Paldontologie und Descendenzlehre, p. 241. 



