108 LECTUEES ON BIOLOGY 



tion contradicts this assumption, for they are largely inhabitants 

 of extensive basins for which the danger of a sudden drying-up 

 did not exist. Lung-respiration would therefore have been 

 useless to them. 



The Carboniferous system is characterized by a much higher 

 degree of organization. There are land-plants, ferns, lycopodia 

 that grow to the size of big trees, giant ' horse-tails ' and palms ; 

 in the forests, spiders, scorpions, myriapoda and numerous 

 species of insects which appear here for the first time in con- 

 siderable numbers. In the swamps we see the first amphibians, 

 the forerunners of the Stegocephala, an Order which develops and 

 flourishes in the Permian, and becomes extinct in the Triassic 

 formation. To them belong the most powerful amphibians 

 that ever existed, as for instance the ungainly Anthracosaurus, 

 an animal of a large salamander-like structure, or the still 

 more enormous Mastodon, whose skull alone exceeded one metre 

 in length. Wonderfully preserved skeleton-parts and skulls of 

 this prehistoric monster have been found in the alum slates of 

 Oedendorf, in Wiirtemberg. 



The Carboniferous is followed by the Permian system. 

 Here the amphibians flourish and forerunners of the reptiles 

 appear, to reach afterwards in the Triassic and Jurassic forma- 

 tions their world-wide distribution and highest development. Of 

 all fossils the reptiles attract the particular interest of laymen 

 and scientists alike on account of their weird forms and enor- 

 mous dimensions. Among them we find the true giants of 

 prehistoric times, who conquered land, air, and water. The 

 reptiles of the Permian system are still unimportant forms, 

 belonging to the two Orders of Ehynchocephalians and Thero- 

 morphs. Of the former only one genus has survived, the famous 

 Tuatara of New Zealand (Hatteria punctata), but owing to the 

 persecution by Maoris and the hog it is fast becoming extinct. 

 The Theromorphs ceased to exist towards the end of the Triassic 

 formation. 



The so-called Mesozoic formations, the Triassic, Jurassic, and 

 Cretaceous, are the typical periods of the reptiles. The seas 

 are inhabited by the Ichthyosaurus, Plesiosaurus, and many other 

 weird forms. In its appearance the Ichthyosaurus, which 

 probably reached a length of 12 metres, resembled a dolphin. 



