l68 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



" The teeth are rather distantly grooved for some distance above the base. They are 

 of different sizes; the smaller are compressed, and with fore and aft cutting edges. The 

 external surface of the dentary bone is marked with short oblique grooves along its middle 

 region; above these are grooves which inosculate, forming a figure like an open net dragged 

 in the long direction. 



"Excepting the grooves the teeth are smooth. The smaller ones are close together 

 and their crowns are curved backwards; the larger ones are at more remote intervals; both 

 have enlarged bases. Whether both forms are in the same series I can not determine. 

 There are from four to five of the smaller to an inch. 



Measurements of Type of Leptophractus obsoletus Cope. 



mm. mm. 



Depth of fragment of jaw 75 Width of paired median scuta 56 



Length of smaller teeth 19 Width of single scute 36 



Length of longer tooth 23 Length of single scute 48 



Width of vertex at middle scuta 176 



' ' Some vertebra? were found at the same locality, but there is no evidence as to the 

 species to which they may have pertained. They are short, concave on one end, and 

 probably so on the other. The centrum of one is 12 mm. in diameter ; neural spines injured." 

 (Geol. Surv. Ohio, 11, pt. 11, pi. 39, fig. 3,) 



"A third and larger specimen was found by Professor Newberry during the field season 

 of 1874. It includes an oblique view of one side, and the top of the cranium from the 

 posterior part of the orbits to the end of the muzzle, with the corresponding part of the 

 alveolar region of the dentary bone, with teeth. The bones of the skull appear to have 

 been rather light, and though the surface is irregular, the sculpture consists only of shallow 

 impressions of varying size and intervals. The orbits are also badly defined, but appear 

 to have been large, and separated by a narrow frontal bone. The premaxillary bone is 

 jireserved, and shows clearly the sutures that separate it from its fellow and from the 

 maxillary. A large foramen — perhaps the nostril — separates it from the maxillary, so that 

 it forms an irregular crescent. It supports two teeth, of which the anterior is the larger, 

 but there were perhaps others in advance, as the alveolar border is imperfect towards the 

 end of the muzzle. The anterior two teeth of the maxillary bone are followed by a strong 

 groove which rises towards the sides of the muzzle. At first sight this gives the impression 

 of the maxillo-premaxillary suture, and makes it appear that both the premaxillary bones 

 are preserved, and that the foramen above described separates the premaxillary spines, 

 instead of representing the nostril. The cutting edges of the teeth of these bones have, 

 however, one direction, whence they represent one side of the cranium only; were both 

 sides represented, the directions of the tooth axes woidd be reversed. 



' ' The premaxillary and maxillary teeth exhibit a cutting edge on the outer posterior 

 margin of the distal half; the base of the crown is subround in section. The line-like 

 grooves are distinct but not numerous, their intervals measuring 75 mm. Beyond them 

 the enamel is smooth. The second maxillary tooth is larger than the first, which is equal 

 to the last premaxillary. The third and fourth maxillaries are equal to the second, but 

 the fifth is larger and longer, exceeding all the others. The teeth of the dentary bone 

 differ from those of the upper jaw in having the cutting edge of the crown on the anterior 

 aspect, while the posterior border is obtuse. There is an obtuse cutting edge on the pos- 

 terior margin of the anterior mandibular teeth. 



"This description is derived from an adult animal, as the maxillary teeth in some 

 instances are partially worn away by friction on their anterior and outer faces." 



Measuremen'ts. 



mm. mm. 



I-ength of maxillary bone preserved 146 Diameter of same at base 6 



Length of same supp)rting five teeth 73 Diameter of second at base 8 



Length of first maxillary tooth 15 Length of ba.sis of fifteen teeth of the dentary 145 



