[8] Archhelenis and Archinotis, p. 125-145, 1907.
[9] Proc. Amer. Philos. Soc. Philadelphia, vol. 41, p. 350, 1902.
[10] See Scharff, Distribution and Origin of Life in America, Ch. 11, 1912.
[11] The following references discuss in detail the arrangement of these forms. Ameghino, 1906, Formations Sedimentaires, Anal. Museo Nac. de Buenos Aires, ser. 3, t. 8, p. 287-498: Roth, Los Ungulados Sudamericanos, Anal. Mus. La Plata, t. 5, 1903, p. 1-36: Scott, Princeton Patagonian Expeditions, vol. 6, p. 287-299, 1912: Gregory, Bul. Amer. Mus. Nat. Hist., vol. 27, p. 273-285, 1910.
[12] Princeton Expeditions Reports, Vol. VI, p. 7, 1909.
[13] P. crassus has been described, (loc. cit., p. 425,) based on pm. 2 and 3, of larger size than either of the foregoing but I do not think that the genus can be determined on so small a fragment.
[14] I have abandoned the family term Notohippidae, as the genus used as a basis is very little known, and the forms Ameghino assigns to the family, to my mind, mostly belong with the Nesodontidae.
[15] Scott has restored the head of Leontinia gaudryi with a single median horn, but no specimen in my collection would indicate anything but a pair of nasal horns. See Scott, Mammals of the Western Hemisphere, fig. 138, 1912.
[16] Annales Palaeontologie, 1906, t. 1, p. 28.
[17] Anal. Palaeontologie, t. 1, p. 5, 1906.