EDENTATA OF THE SANTA CRUZ BEDS. 29 1 



Hapalops ; the intercondylar ridge is more prominent and the internal facet 

 less concave. 



The fibula resembles that of H. longiceps, but has a more trihedral and 

 more uniform shaft, which is less thickened proximally and narrower dis- 

 tally ; the distal end is extremely massive. 



MEASUREMENTS. 



Femur, length from head 218 Tibia, width of shaft in middle 024 



" " " great trochanter. .215 " thickness of shaft in middle 018 



" width of proximal end 065 " width of distal end 043 



" " distal end over tuber- " thickness of distal end 029 



osities .074 Fibula, length 144 



' " " con- " width of proximal end 020 



dyles .063 " thickness of proximal end 023 



" " rotular groove 035 " width of shaft in 'middle oil 



Tibia, length 160 " thickness of shaft in middle. . .01 1 



" width of proximal end 066 " width of distal end 025 



" thickness of proximal end 057 " thickness of distal end 025 



The pes (Plate XLIX, fig. 5) departs in some noteworthy respects from 

 that of Hapalops. The astragalus is slightly longer and narrower than 

 that of H. longiceps ; the trochlea is less grooved and the inner condyle 

 less prominent, while the outer one is more so ; the sulcus which invades 

 the trochlea from the distal end is broader and much more extended 

 dorsally ; the external calcaneal facet is somewhat smaller and less con- 

 cave, while the inner one is larger and separated from the former by a 

 broader sulcus; the neck is longer and more oblique, inclining much 

 more strongly toward the tibial side ; the head is narrower transversely 

 and thicker planto-dorsally. 



Unfortunately, the calcaneum is so broken that little can be determined 

 with regard to it; it is plain, however, that the proximal expansion of the 

 tuberosity is much more gradual than in Hapalops and that the two 

 astragalar facets are much more widely separated. The navicular is very 

 like that of Hapalops, but is even shorter proximo-distally and its outer sur- 

 face for the astragalus more convex. The entocuneiform is long, narrow 

 and scale-like ; the proximal end is the widest part and bears an oblique, 

 concave facet for the navicular; at the distal end it becomes narrower 

 and much thicker and articulates extensively with metatarsals I and II. 



The mesocuneiform is even shorter, but broader and thicker than in 

 Hapalops. The ectocuneiform is also shorter and has a relatively narrower 



