BV C. W. DE VIS. 91 



the hinder with a narrow groove near the inner angle. In the 

 3'oung tooth the impression and groove are the terminal limits of 

 an oblique superficial cleft separating the extero-posterior angle 

 from the rest of the tooth, which cleft is traversed and beset by 

 enamel folds and processes; in teeth reduced to a horizontal 

 surface these processes appear in section as a group of sinuous 

 folds occupying most of the centre of the hinder portion of the 

 tooth, and surrounded on the outer side by a long crescentic band 

 of dentine. Diameters 12-7 x 11.1. 



Molars. — (PI. XV. fig. 9). The edge of the anterior talon is on 

 the inner side double. From the inner side of both links low 

 vertical folds descend to the valleys. Two or three strong vertical 

 folds project from each face of the inner half of the fore lobe, a 

 single fold from the anterior face of the hind lobe; a strong 

 tapering fold rises upon the centre of the posterior surface of that 

 lobe. The links are loft}^ and sharp. 



Maxillary. — P.^ (PI. xv. fig. 6). Extracted from its crypt in 

 a forward stage of growth is irregular oblong, with convex angles, 

 diameters 11-9 x 9-0. Outer side nearly straight, inner with a 

 deep impression at its anterior two-fifths. Fore end sloping, with 

 ol)lique folds. Intero-posterior region of crown much dilated, its 

 surface depressed, concave; its edges at each end rising upon the 

 side of the main lobe, and its posterior surface separated from 

 that of the lobe by a wide cleft which does not descend to the 

 base. The concavity of the ledge is traversed longitudinally b}'' 

 a single sinuous ridge-like fold. On the hinder half of the outer 

 side of the crown tapering ridges ascend to the crest. 



P.^ (PI. XV. fig. 5) much mutilated and worn down , to a field of 

 dentine surrounding a patch of enamel, on the surface of which 

 sinuous enamel folds still appear in -section. The inner side of 

 the crown is impressed at its anterior fourth. Diameters 8*5 x 

 8-5. 



Rise and fall of teeth. 



On this point the limited number of specimens afford sparse 

 information. In the upper jaw the penultimate molar appears to 



