76 Prof. Owen on the Reptilian Fossils of South Africa. 



inwards as they descend from the orbits : the lachrymal bones form the upper 

 border of the nasal orifice, and the nasals, 15, and ascending intermaxillary bone, 19, 

 form the anterior borders. The lateral branches of the intermaxillary bone form a 

 thick convex inferior border bending in to the nasal aperture immediately above the 

 alveolar edge : the facial plate of the superior maxillary, 20, slopes into the nasal 

 cavity from behind. Although the present fragment, on which the Dicynodon 

 strigiceps is founded, includes a smaller portion of the skull than that belonging to 

 the Dicynodon testudiceps, the distinctive features of the species are more striking 

 and more strongly marked : it ought perhaps to be referred, in the absence of 

 decisive evidence of the maxillary tusks, to a distinct genus of Saurian reptile. 



A nodule of the dark hard matrix displays a portion of the middle part of the 

 skull of a small species or the young of a Dicynodon, with the inserted base of 

 both tusks (PI. VI. fig. 4.) ; these have the same circular transverse section, the 

 same gentle curvature and oblique direction downwards and forwards as in the 

 Dicynodon lacerticeps ; but the facial part of the skull, anterior to the alveoli of the 

 tusks, appears to have been relatively deeper and longer, and to have been charac- 

 terized by a ridge extending longitudinally, midway between the nasal and alveolar 

 borders : I shall not, however, at present dwell upon further diiferential characters, 

 as these are susceptible of being more satisfactorily determined by the removal of 

 some of the adherent matrix, for which operation there has not yet been time. 

 Sufficient has been removed from the base of the fang of one of the tusks, c, to have 

 exposed the germ of a successional tooth had such existed, but of this there is no 

 trace. The fang of the tooth retains the same size and shape to the base, which 

 is excavated by a moderately deep, conical pulp-cavity. 



Dicynodon Bainii. 



Two portions of the skull of a large Dicynodon exhibit each the base of a tusk, 

 nearly two inches in diameter, the transverse section of which is subelliptical. A 

 portion of the malo-maxillary bone with the beginning of the zygoma may be distin- 

 guished in one of these portions, but the specimens have been considerably crushed, 

 distorted and fractured. The decomposition of the dentine of the tusk into con- 

 centric lamellae is well-displayed in one of these specimens. The regular subellip- 

 tical form of the tusk has not been produced by compression, but is evidently 

 natural to the species, and distinguishes it from the foregoing smaller specimens. 

 I propose therefore to attach to this, the largest species of Dicynodon, the name of 

 the discoverer, Mr. Bain. 



