PALELOTHERHDA 375 
with the Tapiride; the fourth and probably the third upper pre- 
molar approximating in structure to the molars; the upper molars 
have conical outer columns. Helaletes is another closely allied 
form, with similar premolars, but with the outer columns of the 
upper molars flattened. 
Family PALZOTHERIIDE. 
__ Molars (Fig. 155) brachydont, with the valleys between the 
ridges never filled with cement ; upper premolars either simpler than 
Fic. 154.—Restoration of Palceotherium (Upper Eocene). After Cuvier. 
or as complex as the molars ; lower molars with crescentoid ridges, 
and the last of the series with or without a third lobe. Outer 
columns of upper molars flattened. f f 
Orbit (at least usually) confluent a : 
with temporal fossa. Three digits 
on each foot. This family in- 
cludes extinct genera ranging from ( 
the Middle and Upper Eocene to ¢ {Mf 
the Miocene, and passes so gradu- ~ } 
ally into the following one that the 
maintenance of the two can only 
be supported on the ground of 
convenience. The typical genus, 
Paleotherium, was made known to 
Fic. 155.—A half-worn right upper molar of 
science in the early part of the 
present century by Cuvier, who 
restored the skeleton (Fig. 154) 
with a short neck like that of the 
Tapirs, although it has been sub- 
sequently found that the neck 
was considerably longer. This 
Palcotherium magnum. (After Owen.) fF 
External surfaces of outer columns ; @, postero- 
external column (metacone); b, antero-ex- 
ternal column (paracone); ¢, postero-internal 
column (hypocone) ; @, antero-internal column 
(protocone); 4, anterior intermediate column 
(protoconule); ¢, median valley; g, posterior 
valley. 
genus (which may be taken to include Paloplotherium) ranges from 
