UN GU LATA. 
Mamm. 37 
iv. fASTRAPOTHERlA. 
For synonymy and characters of the genera Astrapotherium and Homalo- 
dontotherium and their species, see Lydekker, An. Mus. La Plata, 
Pal. Arg. ii, art. 3, pp. 42-56. 
3. fHOMALODONTOTHERIIDiE. 
+ Homalodontotherium excursion and crassitm, n. spp., Amegiiino, Bol. 
Ac. Cordoba, xiii, p. 320, Tertiary, Patagonia. 
v. +LITOPTERNA. 
The families Proter other iidce and Macraucheniidce, with their leading 
genera and species, defined by Lydekker, An. Miis. La Plata, Pal. 
Arg. ii, art. 3, pp. 56-71. 
4. fPROTEROTHERIIDJC. 
f Proterotherium pyraniidatum , nitens , principals , divorticum , brachy- 
gnathum , intermedium , and mixtum , n. spp., Amegiiino, Bol. Ac. 
Cordoba, xiii, pp. 293-295, Tertiary, Patagonia. 
\Tetramerorhinus forth and lucarius , n. g. & spp., Amegiiino, t. c . 
pp. 295 & 296, ibid. 
iLicaphrium granatum , proclivum , debile, and tenuce, n. spp., Amegiiino, 
/. c. pp. 297-299, t&iaf. 
\Tichodon , n. g., qucidrilobus , n. sp., Amegiiino, £. c. p. 43, 
f Heptaconus, n. g., accr, n. sp., Ameghino, £. c. p. 300, 
\Thoatherium rhabdodon, n. sp., Ameghino, t. c. p. 301, ibid. 
iDiadiaphorus robustus , n. sp., Amegiiino, <. c. p. 303, ibid. 
5. fMACRAUCHENIIMC. 
Scalabrinia, n. nom., Lydekker, An. Mus. La Plata, Pal. Arg. ii, art. 3, 
p. 69 (1893), to replace Scalabrinitherium , Ameghino. 
vi. PERISSODACTYLA. 
6. Equidje. 
For the Argentine Tertiary species of Equus , Hippidium , and Onohippi- 
dium, see Lydekker, An. Mus. La Plata, Pal. Arg. ii, art. 3, pp. 73-77, 
where Hipphaplus , Ameghino, is shown to be inseparable from 
Hippidium. Scott, Tr. Amer. Phil. Soc. xvii, pp. 111-122, is of 
opinion that the genits Equus was evolved in North America, and 
that Anchitherium, in its restricted sense, was off the direct line. 
He arranges the direct ancestral forms of the upper Tertiary from 
above downwards, in the order Protohippus, Desmatippus, Miobippus , 
and Mesohippus ; Anchitherium branching off from Miohippus and 
Hipparion from Protohippus. See also Osborn & WoRtman, Bull. 
Amer. Mus. vi, p. 213. 
