124 



THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



one of the genus. It is possessed by no other form of Carboniferous air-breathing 

 vertebrate, in association with the other characters of the form. 



The boundaries of the premaxillse are indefinite, but what remains of the sutures 

 indicates that the elements were small. No teeth have been detected. The nasal 

 is likewise not clearly defined, but the frontal is an elongate element which occu- 

 pies the space between the orbits and joins the parietal posteriorly. The parie- 



MEASUREMENTS OF THE TXPE OF EOSERPE- 

 TON TENUICORNE. 



mm. 



Median length of skull 26 



Width across squamosal enlargement.. . 30 



Width across base of horns 25 



Length from muzzle to tip of horn 40 



Length of horn 10 



Width of horn at base 4 



Length of orbit 4 



Width of orbit 3 



Interorbital space 6 



Nos. 4472 and 4473, U. S. National Museum, 

 from Linton, Ohio, Coal Measures. 



mm. 



Median length of skull 16 



Maximum width of skull 20 



Length of horn from base 7 



Length of orbit 3 



Interorbital width 3.5 



Length of vertebral column to sacrum . . 33 



Length of femur 5.5 



Length of tibia and fibula 3 



Length of second digit (incomplete) 7 



Length of metatarsal 1.5 



Length of clavicle 6 



Width of clavicle 3.5 



FIG. 25. Restoration of skeleton of Eoserpcton tenuicorne Cope. X 1.5. 



Skull: pmx, premaxilla; n, nasal; }r, frontal; par, parietal; pf, prefrontal; mx, maxilla; pof, postfrontal; po, post- 

 orbital; pp, postparietal; j, jugal; qj, quadratojugal; spt, supratemporal; sq, squamosal; tab, tabulare. 



Skeleton: ic, interclavicle; cl, clavicle; sc, scapula; h, humerus; r, radius; u, ulna; c, carpus; sr, sacral rib (un- 

 certain?); il, ilium; /, femur; fb, fibula; /, tibia; ts, tarsus. 



tals form a large oval space, so characteristic of many of the Carboniferous Micro- 

 sauria, in the anterior third of which occurs the median parietal foramen. The 

 postparietal is almost square, and forms part of the posterior boundary of the skull. 

 The tabulare has the usual position and relations. The prefrontal is ill defined. 

 The postfrontal is small and forms a slender rod on the postero-inner boundary of 

 the orbit. The postorbital is small and its bounding suture with the postfrontal is 



