Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/18

 14 THE EXTINCT BATRACHIA, REPTILIA B•ACHYDECTESI Cope. Proceed. Ac. Nat. Sei., Phila., 1868, 214. This genus is indicated by two rami of a mandible and a portion of a premaxillary only. These, when compared with those of (Estocephalus, and Dendrerpeton, from the same locality, and with others described by authors, are so much stouter, i. e., shorter and more elevated, that they evidently belonged to a genus not hitherto known. The genus further differs from Oestocephalus, in having the teeth of equal size to the poste-rior parts of the series, that is, to the base of the eleA ated coronoid process. The teeth are elongate cylindric cones, with their acute tips turned a little posteriorly The frac-tured ones display a large pulp cas itv. The three premaxillaries presein ed are similar, but without curvature of the tips. They do not exhibit strive or any other sculpture. So far as the remains known go, the genus is nearer Hylerpeton than any other. According to Dawson that genus is provided with a large canine-like tooth, at the ante-rior extremity of the maxillary, on the inner row, which is inserted into a distinct socket. No such tooth appears among those of this genus. The latter does not give any indica-tion of the very elevated coronoid process of Brachydectes, though the external portion of the dentary bone in that region being lost, little can be said about it. Prof. Owen's plate indicates a ramus whose depth at the last tooth enters 81 times the total length. In our species this depth enters about 5 times. BRACHYDECTES :NEWBERRY', Cope. This species is represented by one nearly perfect ramus mandibuli, one dentary bone, and one premaxillary, prob-ably not complete. The dentary bone appears to have been attached by suture to the articular and angular, as its free margin has very much the outline of that suture in Amphiuma and lizards. The coronoid process would also seem to be a part of the same bone as in Amphiuma and Menopoma, and not composed of a coronoid bone as in lizards. It rises im-mediately behind the last tooth, and displays no suture. The lower portion of the dentary is prolonged into an acute angle. This is separated by a deep and wide eon-eavity from the superior posterior prolongation, which is obtuse and rises at once into the coronoid process. Teeth on this dentary seven ; the same number is on the preserved minus ; this number is suspected to be eomplete or naerly so. The teeth terminate at the obvious termination of each ramus, which is, it is true, slightly obscured. These teeth are the longest of the Microsauria in relation to the depth of the ramus, equalling the largest in (Este-cephalus. They are doubtless exposed, as are some of those of the last named genus, by the splitting away of the outer parapet of the dentary bone. As no traces of alveoli have been this rendered visible, I suspect the dentition to have been aeroclont, as in some existing Batrachia. No external surface of the mandible remains, but there are no impressions of sculpture on the matrix. A little external face of the premaxillary displays none.