Animals Before Man 



amphibians of the first rank in magnitude were 

 not known from America, but the Trias of Ari- 

 zona has yielded specimens indicating a creature 

 eight or nine feet in length, larger if anything 

 than its European contemporaries, and of ad- 

 ditional interest from the fact that it is a mem- 

 ber of a European genus (Metopias). The 

 presence of this animal and a peculiar type of 

 crocodile in the two countries shows that the 

 strata are of the same age and that the two 

 continents were very probably united at the 

 time these rocks were forming. Only one or 

 two bones of this great amphibian have so far 

 been found, but fortunately the evidence of 

 these is conclusive. A peculiar and fishlike 

 character of the Stegocephala is that three 

 bones, forming part of the support of the fore- 

 limbs, show on the under side of the body, just 

 as parts of the fin supports of a 'garpike or 

 sturgeon are not buried in the flesh but form 

 part of the armor. Bones like these, developed 

 from the skin (dermal bones) and lying near 

 the surface, are usually ornamented with pits 

 and grooves, and those of the giant amphibians 



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