THE PENNSYLVANIAN PERIOD 



655 



large and diverse. The amount of carbon dioxide in the atmos- 

 sphere could not have exceeded that compatible with this life. 



Fig. 454. Carboniferous Terrestrial and Fresh-water Life. Plants: a, 

 Callipteridium manffieldi Lesq., b and c, Callipteridium membranaceum Lesq., 

 two species of ferns". Land shells: d, Zonites prisons Carp., e, Pupa vermi- 

 lionensis Bradley. These land snails have been referred to genera living at 

 the present time, and although this reference may eventually prove to be 

 incorrect, they are at least close relatives of recent genera. Insects, etc. : 

 f, Euphoberia armigera M. and W., a Carboniferous myriapod or thousand- 

 legged worm; g, Eoscorpius carbonarius M. and W., a scorpion very similar 

 in type to living forms; h, Arthrolycosa antiqua Harger, a spider more primi- 

 tive than recent forms as seen by the segmentation of the abdomen; i, Pro- 

 gonoblattina columbiana Scudd., one of the allies of the modern cockroaches 

 which were the most conspicuous members of the Carboniferous insect fauna. 

 Crustacea: j, Anthrapalazmon gracilis M. and W., k, Palceocaris typus M. and 

 W., two types of crustaceans found in the Mazon Creek nodules; I, Prest- 

 wichia dame M. and W., one of the early allies of the modern horse-shoe crab. 

 (Weller.) 



III. THE FRESH-WATER LIFE 



Besides fresh-water plants, the life of land waters appears to 

 have consisted of fishes, mollusks, crustaceans, probably of the 

 larval forms of certain amphibious insects, and doubtless of many 



