The skull of the present species is fully described by Jaekel. The type specimen does not offer any evidence in support of Jaekel's "perisquamosal," but rather tends to the idea that he is incorrect in his assumption of the fusion of these elements of the skull. The direction taken by the ridges and grooves on the elements preserved indicate a separation between the supratemporal and the squamosal. I do not find that the grooves have the tendency to arise from a common center of ossification in the squamosal, as suggested in the figures of Jaekel. The horn which projects backward from the squamosal is rather large and heavy for the size of the skull, and after curving slightly inward ends in a blunt point and not sharply, as Jaekel figures in his specimens. The vertebral column is indistinctly preserved and I have nothing to add to Jaekel's account given above. In the structure of the pectoral girdle my results are greatly at variance with those of Jaekel. I do not find the remarkable elements which Jaekel has figured (347) in his specimens. On the other hand, I find a normal microsaurian pectoral arch (464), such as has been described for numerous other forms. There are present, distinctly preserved in the type specimen, the scapulæ, the clavicles, and the interclavicle, with the possibility of the coracoid. The peculiar element referred to by Cope as resembling a "lacertilian pubis" is without doubt the left scapula of the animal (plate 16, fig. 1). Its form compares very favorably with that of _Ceraterpeton_ as figured by Woodward (630). The coracoid may be represented by the fragment which lies close to the scapula. The sculptured element lying next to the supratemporal horn of the skull is the right clavicle preserved bottom side up. Of the other two sculptured elements, one is the interclavicle, only a portion of which is preserved. The left clavicle lies beside it. The clavicles in this species have a tendency to assume the triangular shape so common in other species of Microsauria, and the interclavicle, so far as can be determined, was shield-shaped. The upper surfaces of the pectoral elements are marked by grooves for the attachment of the pectoral muscles. [Illustration: Fig. 24. A. Skull of _Diceratosaurus lævis_ Moodie, from the Linton Coal Measures. × 1. _f_, frontal; _j_, jugal; _mx_, maxilla; _n_, nasal; _or_, orbit; _par_, parietal; _pof_, postfrontal; _po_, postorbital; _pf_, prefrontal; _pp_, postparietal; _sq_, squamosal; _spt_, supratemporal; _qj_, quadratojugal; _pmx_, premaxilla; _tab_, tabulare. B. Reconstruction of skull outlines of _Diceratosaurus robustus_ Moodie, from the Coal Measures of Ohio. × 0.75. _fr_, frontal; _f_, jugal; _or_, orbit; _par_, parietal; _pof_, postfrontal; _po_, postorbital; _pp_, postparietal; _qj_, quadratojugal; _spt_, supratemporal; _tab_, tabulare. ]