AXTHONY, FOSSIL MAMMALS FROM PORTO RICO 197 



and the teres major. A verv large entepicondylar foramen is present. 

 The small portion of the distal region represented in the bone indicates 

 a thin expanded condylar region. Greatest width from deltoid to pec- 

 toral ridge, 1-1.5 mm. ; greatest thickness of bone antero-posteriorly, at 

 distal end of pectoral ridge, 13.5 mm. ; diameter of entepicondylar fora- 

 men, 6 mm. 



Badius (Plate IX, Fig. 3). — Only an end of a radius, the proximal 

 half, was in the collection of bones. This seems to indicate a fairly 

 straight flat element not specialized to any marked extent. AYidth at 

 about the middle of the bone, 11.5 mm. : thickness at same point, 5.5 mm. 



Unguinal phalanx (Plate YIII, Fig. 6). — This phalanx, of which two 

 from the fore limbs were secured, is of a strong, compressed and moder- 

 ately curved type. On the articulating surface there is a strong medial 

 keel. Width of phalanx at a mid point, 5 mm. ; depth just anterior to 

 osseous basal knobs, 8 mm. 



Femur (Plate VII, Figs. 1-.!; Plate YIII, Fig. 1). — Both femurs are 

 represented, one complete, except for a small corner of the internal con- 

 dyle, the other being the distal half only. The femur is fairly robust but 

 is not at all massive as in most of the MegalonychidEe. The shaft is not 

 expanded but has a width considerably less throughout the mid portion 

 than at the extremities. Xo great specializations are shown in the muscle 

 attachment areas. The great trochanter does not rise above the head of 

 the femur and there is no trochanteric fossa. There is a well developed 

 lesser trochanter and also a quite prominent crest extending about 30 mm. 

 along the external aspect of the femur about midway of the shaft. The 

 condyles are large with marked tuberosities and a deep intercondylar 

 fossa. Length, 138 mm. ; greatest width across condjdar portion, 39 

 mm. ; mean antero-posterior thickness of shaft, 14 mm. ; greatest width 

 across head and great trochanter, -±0 mm. ; least width of shaft, about 

 one third of distance from cond^des to head, 18 mm.; head of femur, 23 

 mm. in diameter. 



Tibia (Plate YIII, Figs. 2-4) . — Both the tibia are complete. The tibia 

 is but slightly curved and has a quite smooth, normal shaft. All of the 

 facets on the two condyles are well developed. Length, 111 mm.; width 

 across proximal head, 34 mm. ; width across distal head, 26 mm. ; shaft 

 at mid portion, 13 mm. wide X 10 mm. thick. 



Fibula (Plate YIII, Fig. 5). — The one nearly complete fibula, the ex- 

 treme proximal end being broken off, is a slender but strong bone. It has 

 a large articulating surface distally and proximally as well, as is shown 

 by the well-marked facet for the proximal head of the fibula on the tibia. 

 Length, 106 mm. ; cross-section of mid portion, 5 X ''' mm. 



