PROBOSCIDEA. 
313 
sides. The inferior face exhibits two facets, the one wide, the other narrow 
and subvertical. Each of the lateral faces is bounded below by a facet. 
The posterior tuberosity is not very prominent. 
Measurements of the carpals. 
M. 
( transverse. 0.098 
Diameter of the cuneiform ) antero posterior.... 0.074 
( vertical... 0. 037 
Transverse length of the superior face.. 0.075 
( transverse....... 0.057 
Diameter of the magnum } autero-posterior. 0.105 
( vertical.. 0.080 
Antero-posterior length of the superior face.. 0.084 
Width of the principal inferior facet. 0. 052 
A nearly perfect left femur was obtained from near San Ildefonso. It 
is of the elongate type, and the shaft is flattened so as to be transverse in 
its proximal portion. At the middle of the shaft, its external border is 
almost acute. Distally, its section becomes more and more triangular, rising 
to the ridges of the patellar groove. The distal end of the femur is rather 
compressed; the intercondylar fossa being, as in other Elephants, narrow, 
while the patellar groove and ridges are more than usually prominent, the 
inner ridge being most elevated and prolonged on the shaft. 
Measurements of the femur. 
Total length.... 
Diameter at the base of the trochanter | '" 
, 1 fore-and-aft ... 
Diameter at the middle I ^j'se .. 
( fore-and-aft.... 
Diameter of the distal end | transverse. 
Diameter of the head. . .. 
Diameter of the head of a second femur.. 
The heads of the tAvo femora measured are not yet coossified with 
the shafts. 
The characters recorded in the preceding description indicate a species 
of Mastodon which differs from those described by previous authors as 
inhabiting North America, which I have named M. productus. It is un¬ 
necessary to compare it with tlie species of Tetralopliodon (Falc.), to which, 
according to Leidy, the Mastodon minficiis of the Loup Fork beds of 
M. 
0.950 
0.187 
0.100 
0.130 
0.085 
0.180 
0. 225 
0.160 
O.ICO 
