scott: ENTELONYCHIA OF THE SANTA CRUZ BEDS. 
245 
celui dii diplarthrisme du pied est peut-etre le plus notable ; il consiste 
dans l’articulation de l’astragale avec le scapho'ide et le cubo'ide a la fois 
comme chez les perissodactyles stereopternes. Mais, il s’agit certainement 
d’un diplarthrisme acquis independamment de celui des perissodactyles, 
par un modification graduelle de l’astragale taxeopode des Homalodonto- 
theridce ” (p. 61). In a later publication he suppresses the term Entelo- 
nychia, merging it with the Ancylopoda, and distinctly recognizes a rela- 
tionship with the Toxodonta. “Par la disposition de la denture dans 
son ensemble, par la forme g£nerale du crane ainsi que par les parties 
commes du squelette, ces animaux \Leontiniidce\ paraissent constituer une 
transition entre les Homalodontotheriidce et les Nesodontidce ” (’97, 65). 
Roth’s position is very briefly, but sufficiently, stated in his summary. 
“Das Vorhandensein der Pars mastoidea bei den Homalodontotheriden 
zeigt uns aber, dass diese Familie zu den Notoungulaten gehort, wahrend 
bei den Astrapotheriden keine Spur eines solchen vorhanden ist und sie 
folglich nicht zu dieser Gruppe gehoren konnen. In der That zeigt 
auch eine eingehende Untersuchung der Entwicklung des Gebisses der 
beiden Familien, dass dasjenige von Homalodontotherium auf clem 
Grundplan des Zahnsystems der Toxodonten und das von Astrapotherium 
auf dem der Rhinoceriden basirt ist” (’03, 33). 
My own opinion is entirely in agreement with that of Roth, so far at 
least as the relationship of the Entelonychia to the Toxodonta is con- 
cerned. Every known part of the skeleton confirms this view and testifies 
against any connection with the Ancylopoda of the northern hemisphere. 
The points of resemblance to the Ancylopoda upon which Ameghino lays 
stress are essentially but three in number, (1) the bunolophodont teeth, 
(2) the form of the phalanges, (3) the enlargement of the external digit 
of both manus and pes to carry the chief part of the body-weight. 
(1) The difference in pattern between the upper molars of the chalico- 
theres and the homalodontotheres is not accurately expressed by calling 
one bunolophodont and the other lophodont. As a matter of fact, they 
are both lophodont, having well-defined transverse crests, though in the 
former family the antero-internal cusp (protocone) is sometimes, not 
always, isolated. The important difference is in the character of the 
external wall, which in the chalicotheres has two deeply concave cusps 
separated by a prominent mesostyle, as in the titanotheres, palasotheres, 
horses and Litopterna, while the South American family has the almost 
