mm. Length of portion preserved 120 Maximum width of specimen 58 Length of orbit 20 Width of orbit 14 Length of jaw, as preserved 75 Width of jaw at widest part 11 Length of longest tooth 8 Width of tooth at base 4 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 fragmentary skull (American Museum No. 8572 G and 8532 G); a portion of an interclavicle (American Museum No. 8006); two incomplete vertebræ (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 fragmentary 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. [Illustration: Fig. 40. Mandible of Macrerpeton deani new species, from Linton, Ohio. × 0.75.] The present species is the largest amphibian of the Linton, Ohio, Coal Measures, exceeding in skull length that of _Macrerpeton 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 approximately 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 compared 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 _Dendrerpeton_ will form a natural group of early labyrinthodont-like Amphibia.