SCOTT: TOXODONTA OF THE SANTA CRUZ BEDS. 
235 
Nesodon Lydekker, in part; An. del Mus. de La Plata, T. II, 1893, p. 25. 
This is a small animal which differs from Adinotherium by the absence 
of the median upper incisors, giving the dental formula : If, Cf, P i, Ml. 
Phobereotherium silvaticum Ameghino. 
PJiobereotherium silvaticum Amegh.; Enum. sistem., etc., 1887, p. 18. 
Adinotherium silvaticum Mercerat, in part ; Rev. del Mus. de La Plata, 
T. I, 1891, p. 408. 
The only specific description yet given is that the length of “the five 
upper molars” (presumably p—m-) is 105 mm. (’87 b , 18). 
Locality. — Cliffs of the Rio Santa Cruz. 
STENOTEPHANOS Ameghino. 
Stenotephanos Amegh.; Bol. de la Acad. Nac. de Cienc. de Cordoba, T. 
IX, p. 107, 
Stenostephanus Lydekker; An. del Mus. de La Plata, T. II, 1893, p. 24. 
No example of this interesting, but imperfectly known, genus is con- 
tained in the collections at hand and I shall therefore quote Lydekker’s 
account of it, which is the most complete that has yet appeared. “The 
upper molars are characterized by their narrowness, and by the strong 
curvature of the outer wall of the third ; that tooth having the middle 
column very largely developed and consequently two well marked inner 
clefts. . . . The first and second molars . . . seem to have had but one 
cleft; and as this did not extend to the base of the crown, when much 
worn these teeth show a central island of enamel. In the lower jaw, the 
molars are almost if not quite indistinguishable from those of Xotodon; 
but the premolars have complex internal and external folds, and are thus 
quite different from the simple premolars of the latter” (’93, 24). 
Stenotephanos speciosus Ameghino. 
Stenotephanos speciosus Amegh.; Enum. sistem., etc., 1887, p. 14. 
Stenostephanus speciosus Lydekker; An. del Mus. de La Plata, T. II, 
1893, p. 24. 
Lydekker’s account of the species is as follows: “The smaller size of 
the third upper molar serves to distinguish the specimen from the corre- 
sponding tooth of S. plicidens from the Parana.” The upper molars 
