LABYRINTIIODONT BATRACHIANS. 483 



ing Batrachians, their fossil ancestors had an armor of large 

 breast-plates, with smaller scales on the under and hinder 

 part of the body. 



But the largest forms were the true Labyrinthodonts repre- 

 sented in the Carboniferous rocks of this country by Pxtphdes, 

 and in Europe by Antliracosa-urus, Zijfjoxnurnx, and in the 

 Permian beds of Texas by Enjops. Labyrinthodonts also 

 abounded in the Triassic Period, and forms like the Euro- 

 pean LabyrintJiodon or Mastodontosaurus must have been 

 colossal in size. Footprints occur in the >Sul (carboniferous 

 rocks of this country which indicate forms still larger than 

 any yet discovered in the Old World. A large number 

 (thirty-four species, referable to seventeen genera) of medium- 

 sized Labyrinthodonts have been described from the coal 

 measures of Ohio by Cope which were characterized by 

 their long, limbless, snake-like bodies and pointed heads, 

 forming a still more decided approach to the Ganoids. This 

 was the lowest group of Steyocepliala, called Microxniirin by 

 Dawson. 



Thus we have in these Labyrinthodonts synthetic or an- 

 nectant forms, which connect the fishes with the Am- 

 phibians, and on the other hand point to the incoming of 

 the reptiles. They were thus prematuritive, larval forms, 

 which in certain characters anticipated the coming of a 

 higher type of Vertebrate. The reptiles were ushered 

 hi during the Permian Period, the rocks of this age imme- 

 diately overlying the coal measures, though it should be 

 stated that there are obscure traces of reptiles in the Carbon- 

 iferous rocks. It is not improbable that evidence will be 

 found to substantiate the impression that the rcptilrs, 

 together with but independently of the Amphibians, 

 branched off from the Ganoid fishes, or from extinct forms 

 related to them. 



Order 6. Anura. The toads and frogs represent this 

 order, which comprises tailless Batrachians, with the four 

 limbs present, the toes being very long (due to the great 

 length of the calcaneum and astragalus), while the body is 

 short and broad, the skin soft and smooth, scaleless, though 

 small plates are sometimes embedded in it. The lower ja\v is 



