147—6 INDIAN TERTIARY AND POST-TERTIARY YERTEBRATA. 
The arrangement of the families in the foregoing table must be considered 
merely as provisional and liable to considerable future alterations, and it is probable 
that many of the genera included under one family should be referred to distinct 
families. Thus the family Anthracotheridce is considered by Dr. Filhol to include 
only the genera Anthracotherium and Hyopotamus, and it is suggested that even 
these might possibly belong to two families. On the contrary, Dr. Kowalevsky 
would include many more genera than those given in the table, under the same 
heading. Again the genus Acotherulum, which is here classed among the bunodonts, 
is by many placed close to Hyopotamus, and Entelodon is evidently closely allied in 
the form of its skull to Anthracotherium, though its molars indicate close affinity 
to the typical bunodonts. 
Group A: PENTECUSPIDATI. 
Upper molars with fire columns. . 
Family 1. —ANTHRACOTHERIBAE. 
General Characters. — This family, as already stated, may be defined as 
selenodont pig-like animals, in which the upper true molars carry five cusps, or 
columns. These five columns are well displayed in the tooth represented in figure 3 of 
plate XXI Y. The upper molars are divided into a front and hind portion, or ‘barrel,’ 
by a transverse cleft (in the figure the left half of the tooth is the front, and the 
right , the hind barrel)’, the fore ‘barrel’ carries three, and the hinder, two columns; 
of these, the columns at the four angles represent the two ‘ lobes,’ and the two 
‘ crescents ’ of the ruminant molar ; 1 while the middle column on the fore barrel 
represents the anterior wall of the first ‘ crescent ’ of the ruminant molar. 2 In 
describing these teeth in this memoir, the antero-external column (left hand top corner 
of pi. XXIV. fig. 3) will be termed the ‘first outer column’; the postero-internal 
column (right hand top corner of figure) the ‘ second outer column ’; the antero-internal 
column (left hand bottom corner of figure) the ‘ first inner column ’; the postero- 
internal column (right hand bottom corner of figure) the ‘ second inner column ’; while 
the column wedged in between the first outer and inner columns (middle of left side 
of figure) will be termed the ‘ accessory, or fifth, column.’ Similar terms will be 
used in describing the lower molars. 
As far as is known, the full typical complement of teeth was developed in all 
members of the family ; and in many the canine and premolars attained an excessive 
development, simulating to some extent those teeth in the carnivora. The skull was 
elongated, and presented a considerable resemblance to that of the hogs, while the 
hinder part of the lower jaw in many forms has a resemblance to that of 
Merycopotamus and Hippopotamus. 
1 See preceding fasciculus of this volume. 
2 See Gaudry “ Les Enchainements du Monde Animal,” pp. 97—8. 
