The borders of the premaxillæ and the anterior suture of the nasal can not be determined, though they may have had some such arrangement as suggested. The nasal is represented, so far as is determinable, by an oblong element lying between the frontal and the anterior border of the skull. The f rentals are very large and form a portion of the inner border of the orbit. The parietal is probably the largest bone in the cranium and together the two elements form a large quadrangular space in the posterior half of the skull. They inclose the circular pineal foramen. The postparietal is a small element lying on the posterior border of the skull and with the tabulare and a part of the supratemporal forms the projection. The prefrontal is probably a small element, especially if the lacrimal is present. There seems to be an indication of a suture separating the lacrimal from the prefrontal, but this character is not assured. The boundaries of the maxillæ are clear anteriorly. They indicate that this element was elongate, as is usual, and impressions of teeth borne on the mandible would indicate the probability that the teeth were heterodont. In the premaxillary region there is a long, strong tooth preserved, and on the maxillary near the posterior extremity of this bone there are impressions of teeth which are no more than one-fourth as large as the premaxillary one. The borders of the jugal can not be ascertained, since the skull is injured on both sides in this region. Likewise the quadratojugal is conjectural. The boundaries of the postfrontal and the postorbital are clearly ascertained. They together form the entire posterior border of the orbit and send prolongations along the lateral borders of these openings. They are both acuminate posteriorly and these points are inclosed by the tabulare and supratemporal for the postfrontal and by the squamosal and prosquamosal space for the postorbital. The boundaries of the tabulare show this element to be quite large and extending forward into an acumination which is inclosed by the parietal and the postfrontal. The sutures bounding the squamosal have been obscured by injury in removing the specimen and are indeterminable. [Illustration: Fig. 35.--Outline drawing of the skull and skeleton, as preserved, of _Saurerpeton latithorax_ (Cope), from the Linton, Ohio, Coal Measures. Original in U. S. National Museum. × 0.75. Skull: _fr_, frontal; _j_, jugal; _mx_, maxilla; _n_, nasal; _no_, nostril; _or_, orbit; _par_, parietal; _pof_, postfrontal; _po_, postorbital; _pp_, postparietal; _pf_, prefrontal; _pmx_, premaxilla; _qj_, quadratojugal; _m_, mandible; _spa_, supraorbital lateral-line canal; _spt_, supratemporal; _sq_, squamosal; _tab_, tabulare; _y_, pineal foramen. Skeleton: _cl_, clavicle: _c_, carpus; _rb_, ribs; _h_, humerus; _ic_, interclavicle; _met_, metacarpals; _psc_, pectoral scutellæ; _r_, radius; _vs_, ventral scutellæ; _u_, ulna. ]