EOPROTEROTHERIUM 31 
The following table will give what is known in comparing 
the two series. 
PERIOD Upper MOLARS NASALS PES 
Proterotherium Santa Cruz metaconule present normal _ tridactyl 
protoconule and protocone separate 
Eoproterotherium Deseado metaconule present 
protoconule and protocone separate 
Licaphrium Santa Cruz metaconule present normal tridactyl 
Diadiaphorus Santa Cruz metaconule present short tridactyl 
protoconule and protocone fused 
Notodiaphorus Deseado tridactyl 
Thaotherium Santa Cruz metaconule lacking normal monodacty! 
protoconule and protocone separate 
Deuterotherium Deseado metaconule lacking 
protoconule and protocone separate 
Eoproterotherium Ameghino 
Eoproterotherium Amegh., 1904, Anal. Mus. Nac. B. A., ser. 3, t. 3, D- 441. 
The genus is founded on single teeth of the upper molar 
series, which, except for size, are 
very like those of Proterotherium. 
Limbs, etc., are unknown, so _ that 
this genus is simply a carrying back 
of the Proterotherium line into 
the Deseado. We. found no teeth of 4... 4. moproterotherium 
inaequifacies, third upper mo- 
thisr:form, ,but one species, has. beem) pe aera tise. C, Prothero- 
described, E. inaequifacies, of which {Ri mote natural ‘size, 
I reproduce Ameghino’s figure com- ““* “mem 
pared with Proterotherium, which shows this species to 
have the metaconule better developed. 
Notodiaphorus gen. nov. 
The basis of this genus is particularly a hind limb found 
associated which is much less developed than the Santa 
Cruz genus Diadiaphorus to which it is most nearly related. 
These two genera are unique in having the ectal facet on 
