236 
PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 
“present the characters already noticed, while the lower molars are 
almost indistinguishable from those of Xotodon ; the premolars being of 
Fig. 42. 
Stenotephanos speciosus. Fragment of right upper maxillary with the molars in place. About 
natural size. Type specimen, La Plata Museum. 
a very complex type. The length of the space occupied by the five lower 
teeth [p3-m-3] is three inches ” (’93, 24-5). 
Locality. — Cliffs of the Rio Santa Cruz. 
GENERA INCERTaE SEDIS. 
Ameghino has named a number of genera, concerning which very little 
is known and which will therefore be merely listed, as none of them is 
represented in the collections at my disposal and I have no information 
to add to the little already published. I am not in a position to express 
an opinion as to the validity of these species. 
RHADINOTHERIUM Ameghino. 
Rhadinotherium Amegh.; Enum. sistem., etc., 1887, P- 1 %- 
Nesodon Mercerat, in part; Rev. del Mus. de La Plata, T. I, 1891, p. 394. 
Rhadinotherium limitatum Ameghino. 
Rhadinotherium limitatum Amegh.; Enum. sistem., etc., 1887, p. 18. 
Nesodon limitatum Mercerat; Rev. del Mus. de La Plata, T. I, 1891, 
p. 403. 
PALzEOLITHOPS Ameghino. 
Lithops Amegh.; Enum. sistem., etc., 1887, p. 15. (Preoccupied.) 
Palceolithops Amegh.; Rev. Argent, de Hist. Nat., T. I, 1891, p. 240. 
