86 FAUNA ANTIQUA SIVALENSIS. 



Fig. 1 a. — Lateral view of same specimen. The orbit is Dot elevated 

 above the plane of the frontal. 



Fig. 1 b. — 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 crescen tic form outwards, not un- 

 like that of ruminants, and the grinding surface slopes outwards, as in 

 the description given by Cuvier of Hippopotamus minutus. 1 



Fig. 1 c. — Posterior or occipital view of same specimen. 



Figs. 2, 2 a, and 2 b. — M. dissimilis (var. major). Imperfect cranium 

 including muzzle. Lateral, upper, and palatal views. — B.M. 



Figs. 3, 3 a, and 3 b. — M. 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, 4 b, and 4 c. — 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 froni 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 loAver with the anterior margin, corresponding to the lower end of 

 the symphysis, is marked by a distinct tuberosity or projection down- 

 wards (rr). 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 5 b. — M. dissimilis (var. minor 2). Cranium; upper, 



1 ' In the true molars of the Meryco- 

 potamus, the inner demi-eones are simply 

 convex, and the two grooves on the outer 

 arcs form a deep external depression, at 

 the bottom of which is the convex ridge. 

 The antero-posterior cleft, iustead 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 arc of the Runii- 

 nant molar. The cement at the bottom 



strong ragged ridge along the inuer half 

 of the base of the crown forms the chief 

 distinction between the molars of the 

 Meryeopotainus and those of the Rumi- 

 nant. The teeth in the lower jaw make 

 a similar approximation to the Rumi- 

 nant t^'pe, 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 



of the valleys is thinner than in the i canines and incisors closely accord with 

 Ruminants ; the enamel is as rugose as | the Hippopotamic type of these teeth.' 

 in the Giraffe or Sivathere; but the Owen':? -Odontography.' i. .306. 



