THE AMERICAN COAL MEASURES BRANCHIOSAURID^. 57 



and the character of the ventral armature all clearly bespeak a close relationship 

 with Branchiosaunis, Melanerpeton, Pelosaurus, and other European branchiosau- 

 rian forms from the Upper Carboniferous and Lower Permian. 



The above-described species, with others given below, is the earliest geological 

 evidence of the Branchiosauria, since the oldest European forms are from the Ste- 

 phanian (Upper Carboniferous) , which probably lies somewhat above the horizon of 

 tin 1 Allegheny series of North America. The presence of the Branchiosauria in 

 America is of considerable interest in the bearing it has on the distribution and 

 migration of the Paleozoic animals. Knowledge of how the group came to occur 

 in such widely separated localities in approximately contemporary geological strata is 

 an unsolved problem of paleontology. It is possible that the piscian ancestors of the 

 Amphibia migrated across or along the borders of the seas and began the amphibian 

 phase of development independently in the two continents. That evolution should, 

 in this case, have followed almost exactly parallel lines seems incredible. 



MEASUREMENTS. 



mm. mm. 



Length of entire animal 49 Length of rib 1.5 



Length of head in median line 6.5 Length of scapula . 3 



Width of head at posterior border 8 Maximum width of clavicle . ... 2 



Length of orbit 2.5 Length of humerus 2.5 



Width of orbit 2 Length of ilium ... 1.5 



Interorbital space 2 Length of femur . 



Length of the vertebral column 33 Length of tibia . 1.5 



Length of the vertebral centrum in dorsal series. . 0.5 Length of tail impression . 21.5 



Length of trunk from base of skull to sacrum. ... 22 Width of tail impression at base . 4 



Genus EUMICRERPETON Moodie. 

 MOODIE, Kans. Univ. Sci. Bull., vi, No. 2, p. 330, 1912. 



Type: lEumicrerpeton parvum Moodie. 



The genus is established on three well-preserved specimens representing nearly 

 the entire anatomy. The generic characters are found in the very broad posterior 

 table of the skull, with its short length, reduction of tympanic notch, and shortness 

 of body. The body-length of Eiaiiicrcrpeton (plate 5, fig. i) is less proportion- 

 ately than that of other closely allied genera. Other generic characters are found in 

 the sharp postero-lateral angle of the skull, and it is to be distinguished from Micrer- 

 peton, especially, by the short, stumpy limb bones. The narrow, elongate eye, 

 placed close to the edge of the skull, is a character not observed hitherto in the 

 Branchiosauria. The genus is closely allied to Branchiosaunis of Europe. 



Eumicrerpeton parvum Moodie. 



MOODIE, Proc. U. S. Nat. Mus., 40, p. 430, fig. i, 1911. 



MOODIE, Kans. Univ. Sci. Bull., vi, No. 2, pp. 331-336, pi. 3, figs. 3 and 4; pi. 4; pi. 5, fig. i; pi. 6, figs, i 



and 2, 1912. 



MOODIE, Amer. Nat., 44, pp. 367-375, figs. 1-4, 1910. 

 MOODIE, Science, n. s., xxxi, No. 789, p. 233. 



Type: Specimen No. 803, Yale University Museum. Other specimens, No. 

 802, Yale University Museum, and No. 4400, U. S. National Museum. 



Horizon and locality: Mazon Creek shales, near Morris, Illinois. 



The impression of the outline of the entire body is preserved (plate 3, figs, i and 2) 

 in three specimens, and in all are found molds and impressions of the alimentary 



