Records of the Geological Survey of India. 
148 
[vol. a* 
■with irregular longitudinal stria?; there is a slight wavy cingulum surrounding the base of 
the crown. The premolars are strikingly like those of Anthmcotherium. 
Upper molars, —The upper molars are nearly square-crowned teeth, surmounted by four 
unsymmetricaJ cones {specimensfigured in “ Fauna Antique Sival.ensis” plate 02, fig. 17, 
and Givens “ Odontography,” plate 140, fig. 8). The cones are separated by a cruciform 
valley, of which the transverse division is by far the deeper ; the general type, therefore, on 
which the tooth is formed is the same as that of the simpler teeth of Stis, Tetranonodon, and 
Hippopotamus. On the inner sides both inner and outer cones are perfectly symmetrical; 
the outer surfaces, however, of both pairs of cones are concave; these surfaces of the inner 
cones are simply concave, while the same surfaces of the outer cones have a median ridge 
running down the concavity, and a shorter lateral ridge at each of the outer angles of the 
cone. Bv this means a Ruminant form of the tooth has been engrafted on the original 
simple form ; in Ruminants the transverse valley becomes almost obliterated by the approxi¬ 
mation of the cones, and only remains as the groove separating the inner divisions of the 
cones (or barrels); on the outer side the transverse valley does not penetrate the crown, and 
its place is only marked by the division between the summits of the lobes; further, the 
antcro-posterior valley becomes deeper between the cones (or barrels) and is divided into two 
portions by the united edges of the inner cones; the outer surfaces of the barrels, instead of 
being concave and sloping towards the inner side, as in Merycopotamus, become flat and 
vertical, retaining, however', the ridges found on the tooth of Merycopotamus. 
The upper molars of Merycopotamus are surrounded by a distinct cingulum, less 
boldly marked on the outer surface than on the other three; and their enamel is rugose. 
Compared with Hyopotamus. —The molar teeth of Merycopotamus are distinguished 
from those of Hyopotamus (another ILippopotamoid genus, showing Ruminant affinities in 
the form of its molar teeth) by those of the latter being less altered from the original Tetra- 
conodon type ; in the teeth of Hyopotamus tin; ridges which occur at the outer angles of the 
outer pair of cones of the molars of Merycopotamus are absent: in consequence, the outer 
border of the molars of the former geuus forms a simple wavy line. There is also in the 
teeth of Hyopotamus the absence of the vertical ridge occupying the middle of tire external 
surfaces of the outer cones which occurs in Merycopotamus. The inner cones, moreover, in 
the European genus are less concave on the outer side, and more regular in shape than in the 
Indian genus ; while the former are further distinguished by the presence of a small addi¬ 
tional cone in the re-entering angle on tlie anterior side of the first pair of cones. The 
molars of Merycopotamus are distinguished from those of Die hod on (with which Pictet 
compares them) by the completeness of the transverse valley in the former. 
Lower molars. —The lower molars, like the upper, are intermediate between those of the 
Pig and Ruminants; they consist pf four cones, of which the outer pair are the highest, 
separated by a cruciform-valley, of which the transverse portion is by far the deeper; the 
latter valley is shallower at the inner than at the outer side; the external surfaces of both 
inner and outer cones are nearly vertical; the inner surfaces of the outer pair of cones are 
concave; the posterior surface of the hinder one of the outer pair of cones is vertically 
grooved; an indistinct cingulum surrounds the base of the crown; there is no accessory 
tubercle at the outer extremity of the transverse valley ; following .the usual rule of the 
Artiodactyla, the third lower molar has time lobes, the hinder lobe consisting of a single 
cone, which corresponds to the outer cone of the middle pair. 
The teeth are distinguished from those of Sits and its allies by the greater width of 
the transverse valley, and by its becoming shallower at its inner extremity, and b} r the longi¬ 
tudinal valley being broken up into two portions, which form the pits between the outer and 
inner cones. 
