244 
PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 
THE SYSTEMATIC POSITION OF THE ENTELONYCHIA. 
The early view of Flower (’84, 181) and of Lydekker (’86, 160) that 
Homalodontotherium was allied to the rhinoceroses, which was sug- 
gested when nothing was known of these animals save the teeth, may 
be disregarded, especially as Lydekker subsequently adopted a very 
different opinion (’96, 77). Of late years, but two conflicting opinions, 
each in somewhat varying forms, concerning the systematic position and 
relationships of the Entelonychia have been expressed, (1) that of Ame- 
ghino, that the Entelonychia are to be referred to the Ancylopoda, and 
(2) Roth’s view (’03) which makes them a part of his “ Notoungulata,” 
a term equivalent to the “Toxodontia” as here employed. Lydek- 
ker’s opinion, which may be regarded as essentially like that of Roth, 
assigns the Homalodontotheriidae to the suborder “ Astrapotheria,” but 
holds that the Toxodonta, Typotheria, Astrapotheria and Litopterna 
“have originated from a common ancestral stock” (’96, 77), which is 
merely adding the Astrapotheria and Litopterna to the Notoungulata, a 
procedure for which much may be said. 
Ameghino’s views on this subject may best be made clear by a series of 
quotations: “Cette apparence lophodonte des molaires et premolaires de 
X Homalodontotherium est due k l’age tres avance des individus figures. 
Cette denture est en realite buno-lophodont, les deux lobules internes des 
molaires superieures (protocone et hypocone) restant longtemps separes en 
forme de tubercules pointus” (’94 0 , 56). “Les relations de parente entre 
les Homalodontotheridce et les C. ha lie other idee se manifestent d’une maniere 
tr£s evidente par la forme crochue des doigts, par la disposition des sur- 
faces articulaires distales des metacarpiens et des metatarsiens, par la 
forme des articulations proximales des premieres phalanges, par les pha- 
langes ongueales qui ont une forme semblable et sont fendues perpen- 
diculairement k leurs extremites, par le caractere tout particulier d’avoir 
le doigt externe de chaque pied plus developp£, et enfin par le caractere 
encore plus singulier d’etre les doigts externes des pieds ceux qui sup- 
portaient le poids principal du corps. 
“Tous les caracteres par lesquels les Homalodontotheridce s’eloignent 
des Chalicotheridce . . . indiquent un degre devolution peu avancee” 
(pp. 60, 61 ). “ Les caracteres qui distinguent les Chalicotheridce indiquent 
au contraire un degre d’ evolution tr£s avancee. Parmi ces caracteres, 
