86 FAUNA ANTIQUA SIVALENSIS. 
Fig. 1 a.—Uateral view of same specimen. The orbit is not elevated 
above the plane of the frontal. 
Fig. 1 6.—Palatine view of same specimen, showing three molars and 
one premolar. The absence of the trefoil wear of the coronals is to be 
noted. Each pair of collines takes a crescentic form outwards, not un- 
like that of ruminants, and the grinding surface slopes outwards, as in 
the description given by Cuvier of Hippopotamus minutus.* 
Fig. 1 c.—Posterior or occipital view of same specimen. 
Figs. 2, 2 a, and 2b.—WM. dissimilis (var. major). Imperfect cranium 
including muzzle. Lateral, upper, and palatal views. —B.M. 
Figs. 3, 3a, and 3 b.—WM. dissimilis (var. major). Cranium ; upper, 
palatine, and lateral views, showing three molars, four premolars, and 
canines. The second left and first right premolars have dropped out. 
The left canine is seen to be remarkably curved downwards, first out- 
wards and forwards, and then slightly backwards.—B.M. 
Figs. 4,4 a, 4b, and 4¢.—M. dissimilis (var. major). Lower jaw, 
right side; outer, upper, and inner views. The alveoli of three in- 
cisors and first three premolars are empty ; the three molars and fourth 
premolar are present, but, excepting hindmost molar, are well worn ; 
the canine is curved upwards and outwards and slightly backwards at 
the tip; it is pear-shaped on section, as in Hipp. Sivalensis. The de- 
scending process is well seen, and is separated from the horizontal ramus 
by a considerable indentation. The anterior extremity of the horizontal 
ramus is much more oblique than in H. Sivalensis, and the junction of 
the lower with the anterior margin, corresponding to the lower end of 
the symphysis, is marked by a distinct tuberosity or projection down- 
wards (7). One large mentary foramen is seen on outer surface below 
the fourth molar, and between this and the canine the bone is deeply 
channelled; the molar ridges are almost parallel, and there is very little 
widening of the symphysial portion of the jaw. The great peculiarity 
of the jaw is the general slenderness of its proportions and the inequality 
of its depth. From the descending process it first becomes deeper, and 
then it gradually diminishes towards the symphysis. In Hipp. Sivalensis 
the jaw is straight, thick, and massive, as in Plate LXI. 3, 4, 5.—B.M. 
Figs. 5,5 a, and 5b.—WM. dissimilis (var. minor?). Cranium; upper, 
1 «Jn the true molars of the Meryco- 
potamus, the inner demi-cones are simply 
convex, and the two grooves on the outer 
ares form a deep external depression, at 
the bottom of which is the convex ridge. 
The antero-posterior cleft, instead of 
being straight, as in the Hippopotamus, 
forms two bends convex inwards, and 
thus the symmetrical pattern of the 
Hippopotamic molar is converted into 
the double-crescentic are of the Rumi- 
nant molar. The cement at the bottom 
of the valleys is thinner than in the 
Ruminants ; the enamel is as rugose as 
in the Giraffe or Sivathere; but the 
strong ragged ridge along the inner half 
of the base of the crown forms the chief 
distinction between the molars of the 
Merycopotamus and those of the Rumi- 
nant. The teeth in the lower jaw make 
a similar approximation to the Rumi- 
nant type, but the anterior and posterior 
primary divisions are separated by a 
wider cleft; the last molar has a third 
hinder lobe; the lower molars are im- 
planted by two roots. The forms, pro- 
portions, and relative position of the 
canines and incisors closely accord with 
the Hippopotamic type of these teeth.’ 
Owen's ‘Odontography,’ i. 566. 
