165—24 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
u Records of the Geological Survey of India ” for 1876, 1 and a supplement to the 
same was published in the following year. 2 All the more important notices of this 
species previously published are recorded in those papers, and as no additional 
remains are described in the present memoir only a summary of its more important 
characters will be given. 
Characters . — As far as can be determined from the remains known to us, 
Merycopotamus dissimilis was probably either a pente — or tetradactylate pig-like 
animal of about the size of the wild boar. Its dentition comprises, as far as is 
known, the complete placental mammalian series. The canines are relatively 
large, approximated to the incisors, but separated by a long 1 diastema ’ from the 
premolars. The anterior premolars are sharply pointed like those of Antliracotherium 
and Hippopotamus : the anterior premolar is placed close to the succeeding tooth, a 
character in which Merycopotamus agrees with the pig, and differs from the 
hippopotamus. The upper true molars, of which there is an excellent figure in 
plate LXII. figure 17 of the “Fauna Antiqua Sivalensis,” 3 are selenodont teeth with 
four distinct columns, and with a well-marked ‘ cingulum ’ on their inner halves : 
their enamel is coarsely rugose. The external surfaces of the outer columns slope 
towards the centre of the crown, and their basal angles are folded over their centres, 
which thus become concave : a well-marked ridge occupies the median line of each 
of these surfaces : the loop connecting these surfaces does not project on the external 
surface of the crown. The crowns are remarkably low, and a rudely cruciform 
valley, open to the bottom, separates the four columns ; — characters by which the 
teeth are readily distinguished from those of the true ruminants. With the 
exception of the absence of the fifth lobe, and the smaller development of the loop 
connecting the outer columns, the teeth present a striking resemblance to those of 
Ilyopotamus palceindicus ; the basal angles of the external surfaces of the outer 
columns are, however, more produced in the former. The lower molars are of the 
general type of those of the selenodont Suina. 
The cranium presents a considerable resemblance to that of the hippopotamus, 
which is, perhaps most marked in the occipital region fcompare “ F. A. S .,” plate LX. 
fig. 4c, and plate LXVIII., fig. 15/: the parietal region is, however, longer and more 
compressed, the orbits less prominent, and the infraorbital portion longer and less 
expanded at its extremity. In all the points in which the skull of Merycopotamus 
differs from that of the hippopotamus, it agrees with the skulls of the Anthracotheridce 
and the true pigs. The skull is shorter than the skulls of those species of Hyopotamus 
of which the skull is known, and also differs by the presence of a distinct larmial 
cavity. The most striking affinity to the hippopotamus is displayed by the form of 
i Vol. IX., p. 144, et. seq., on page 153, line 12 from the bottom, the words R ippopotamidce and Anthracotheridce should 
he transposed. 2 Ibid Vol. X., p. 34. 
3 A woodcut of a singld molar is given in Professor Owen’s memoir on Ilyopotamus , cited above ; another figure in the 
“Odontography” of the same author, (pi. CXL., fig. 8); and a third by Professor Gaudry. (“ Les Enchainements du 
Monde Animal, etc.,” p. 98, fig. 124.) 
