ON A NEW SPECIES OF DICYNODON 133 
sharp, and is developed from the maxilla, close to its upper boundary. 
The supero-lateral ridge is situated on the sides, and the median 
ridge on the middle, of the premaxillary and nasal bones. The 
external bony nasal apertures are placed in the upper part of the 
snout, about $ths of an inch in front of the orbit ; they are irregularly 
oval, and about an inch long by 75ths of an inch wide. They are 
1} inch apart, but appear to have communicated with one another 
above the thin bony ethmovomerine septum. In another specimen 
the bony plate which roofs them in above and in front is wider than 
in that figured; but in none does it seem to have formed an over- 
hanging ledge. 
The extreme termination of the snout is apparently wanting in 
all my specimens; it was probably curved downwards and convex 
forwards, but, I suspect, less so than in other Dicynodons. Below 
the infero-lateral or alveolar ridge, the sides of the mawilla slope 
abruptly inwards, and are then continued downwards to unite with 
the palatine bones. 
The projecting ends of the tusks are broken off at about two 
inches from the ends of their fangs in the specimen figured. In the 
transverse sections (Pl. XXII. [Plate 8] figs. 3-6), it is seen that no 
trace of the tusk is visible in that taken through the external nostrils 
(fig. 3); while in that taken {ths of an inch further forwards (fig. 4), 
the section of the walls of the tusk, which measures nearly {ths of 
an inch in diameter, and has a pulp-cavity 3th of an inch less, is very 
visible. The pulp-cavity gradually diminishes anteriorly, so that 
close to where the tusk is broken off, in fig. 6, its diameter is not 
more than equal to that of its wall, and, as I observe in other speci- 
mens, it becomes still less further forwards. The tusks seem to have 
been nearly straight in this Dzcynodon, or to have been but very 
slightly curved. 
The occipital bones (PI. XXIII. [Plate 9] fig. 2) are united into 
a great vertical quadrate plate, 24 inches high by 44 inches broad. 
The upper edge of this plate exhibits a median notch, on each side 
of which it passes outwards, nearly horizontally, but with a slight 
upward convexity, for 14 inch. It then curves downwards until it 
joins the lateral face, which at a short distance below the junction 
presents a deep notch. Down to the level of this notch the occipital 
surface is nearly flat; but below the notch, it presents an oblique 
excavation on each side, succeeded by a very strong convexity, whose 
longitudinal axis is directed downwards and outwards, and which, by 
its truncated end, apparently abuts against the quadrate bone. The 
occipital foramen which lies in the midst of the occipital face of the 
