FOSSIL VERTEBRATES — AMPHIBIA 511 
and perfection of the limb bones, especially the articular sur- 
faces which, as a general thing, are not well developed even in 
the recent amphibians. 
Melosaurus from the Keupfer sandstone of Orenbourg in 
Russia was, so far as the imperfect specimen can be interpreted, 
quite similar to Avchegosaurus, it has been suggested that it 
may be the same genus ; if this is true, it would indicate a very 
wide range of distribution for the animal. 
Trimerorachis and Eryops are from the Permian deposits of 
Texas in the United States. Only the lower division of the Per- 
mian, the Wichita division of the Texas geologists, has yielded 
any vertebrate fossils, but in this horizon there is a somewhat 
abundant fauna of amphibians, reptiles and fishes. In the 
neighborhood of Danville, in eastern Illinois, there have been 
found remains of the same amphibians that are found in the 
Texas deposits; the area is only a small one and is regarded as 
the course of an old river that has cut its bed through the 
underlying Carboniferous rocks. Some fragments of the same 
animals have been found in New Mexico. Of the genus, Eryops, 
Cope, the describer says, “this is the largest of American 
batrachians, the skull measuring a foot wide by eighteen inches 
long. It was very abundant constituting with the reptilian 
genus, Dimetrodon, the most prominent type of the Permian 
fauna in this country. The vertebral column is slender when 
compared with the size of the limbs and especially the head.” 
Of the genus 7rimerorachis he says, “the head of 7. msignis is 
wide, flat and rounded, and its superior surface is strongly 
wrinkled. The lyriform mucous grooves do not extend behind 
the orbits. This was an abundant species during the Permian 
time in Texas, and probably possessed aquatic habits.”’ 
Acheloma and Antsodexis are forms from the Permian of 
Texas that are less well known than the foregoing and are per- 
haps synonymous with Eryops. 
EmBOLERIMI.— These are perhaps the most interesting of the 
Layrinthodontia; as already indicated they are distinguished by 
the fact that the vertebrae are made up of two rings formed by 
