1 84 



THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



DESCRIPTION OF ADDITIONAL MATERIAL OF MACRERPETON HUXLEYI. 



The additional material of this species which has come to hand consists of an 

 almost complete skull (American Museum No. 2933, two portions); another frag- 

 mentary skull (American Museum No. 8572 G and 8532 G) ; a portion of an 

 interclavicle (American Museum No. 8006) ; two incomplete vertebrae (American 

 Museum No. 8007) ; and another fragmentary element possibly representing a 

 scapula of this species (American Museum No. 8008). 



The skull has essentially the shape outlined (462) from a study of the fragmen- 

 tary type specimen. The muzzle was drawn slightly too broad, but otherwise the 

 restoration is fairly accurate. The specimen is distorted and imperfect, but enough 

 is preserved to give a good idea of the shape and something of the structure of the 

 skull. A portion of the obverse is preserved. The back part of the skull is broken, 

 so that the occiput can not be studied. 



The length of the skull is one and two-fifths the greatest breadth (across the 

 orbits). The cranial elements are deeply marked with pits and short, shallow 

 grooves. On the left mandible these pits are in a very distinct row, the operculo- 

 mandibular lateral line. 



Macrerpeton deani new species. 



Type : Specimen No. 2934, American Museum of Natural History. 



Horizon and locality: Linton, Ohio, Coal Measures. (Plate 21, figs. 1,2.) 



The material for this species consists of the posterior half of the left mandible 

 and a portion of the right antero-lateral surface of the skull, both incomplete. The 

 reasons for regarding the species 

 as distinct are the large size of 

 the specimens and the manner of 

 the sculpture, as well as the 

 shape of the posterior end of the 

 mandible. 



The present species is the 

 largest amphibian of the Linton, 

 Ohio, Coal Measures, exceeding 



in Skull length that Of Macrer- FIG. 40. Mandible of Macrerpeton deani new species, from Linton, 



peton huxleyi by twice. The 



largest skull of Macrerpeton huxleyi which has so far come under my notice is 120 

 mm. in median length. There are 3 skulls of this species known, all of approxi- 

 mately the same size. The skull of Macrerpeton deani must have reached or exceeded 

 a foot in median length. The only species with which it can at all be com- 

 pared are Eobaphetes kansensis Moodie and Baphetes planiceps Owen, but it is 

 clearly distinct from all other genera of Linton Amphibia. It is possible that when 

 better known Macrerpeton, Eobaphetes, Baphetes, Erpetosaurus, and possibly Dcnd- 

 rer peton will form a natural group of early labyrinthodont-like Amphibia. 



The mandible is similar in structure to that of the labyrinthodonts, with the 

 elements marked by radiate flutings. I can detect no evidences of a lateral-line 



