654 GEOLOGY 



The labyrinthodonts were doubtless the largest amphibia of the 

 period, some of their skulls reaching a length of half a meter or 

 more. 



Not much is known of the food and life-habits of the amphibia, 

 but from their teeth it is inferred that they were predaceous. In 

 Nova Scotia, Dawson took thirteen skeletons representing different 

 species of amphibians from a single sigillarian stump. Since land 

 shells and myriapods are found in stumps with the amphibian 

 skeletons, it has been inferred that some of the amphibians were 

 climbers, and lived on mollusks, myriapods, and similar land life. 



The amphibians of different continents were so similar as to 

 suggest great freedom of communication and migration. This 

 free intercontinental migration seems to have come to an end by the 

 close of the Pennsylvanian period. 



The marked development of insects. 1 Several hundred species 

 of Carboniferous insects have been identified from the American 

 Coal Measures, and a comparable number from European. They 

 were still, for the most part, of rather primitive types, often uniting 

 characters not now found in the same order. The orthopters (cock- 

 roaches, i, Fig. 454, locusts, crickets, etc.) were greatly in the lead, 

 followed by the neuropters (represented by ancestral mayflies). 

 These two orders include about 90 per cent of the known insects. 

 Hemipters (bugs), which had appeared earlier, and possibly coleop- 

 ters (beetles) were present, but no fossils of bees, butterflies, or moths 

 have been found, and there is no probability that they existed, 

 since the flowering vegetation on which they depend had not yet 

 appeared. There is also no record of flies. The evolution of insects 

 was therefore one-sided. Curious forms were developed within 

 the orders which lived, and remarkable dimensions were attained. 

 spreads of wing of a foot or more being reported. 



Spiders and myriapods (Fig. 454) were plentiful. Scorpion* 

 (g) also were present, and several species of land snails (d and e) 

 have been identified. The air-breathing community had become 



1 Scudder, Bull. No. 71, U. S. Geol. Surv., 1891, and works there 

 to. Brongniart, Researches pour servie a 1'histoire des Insectes Fossilcs drs 

 Temps Primaires, 1894. Dawson, J. W., Synopsis of the air-breathing 

 animals of the Paleozoic in Canada u to 1894. 



