EDENTATA OF THE SANTA CRUZ BEDS. 199 



while the third trochanter is much larger and more prominent than in 

 Megalonyx or Nothrotheritim, the only Pleistocene genera in which this 

 process is retained. The shaft is intermediate in character between the 

 two genera named, being somewhat broader and more flattened than in 

 the latter, less so than in the former ; it is also relatively longer than in 

 Megalonyx, considerably exceeding the humerus in length, while in the 

 Pleistocene genus the two bones are nearly equal ; the anterior or dorsal 

 face of the shaft is slightly convex and its proximal half bears two long, 

 parallel ridges for muscular attachment, which are less prominent than in 

 the last-named genus. The tuberosities are prominent, and the external 

 one is large and rugged, while the inner one is quite small. The rotular 

 groove is somewhat narrower than in Megalonyx and is extended much 

 farther upon the dorsal face of the shaft, with its proximal end distinctly 

 projecting from the shaft, which has an obscurely marked suprapatellar 

 fossa. The condyles are small and present so directly backward as to be 

 concealed when the femur is viewed from the front ; the inner condyle is 

 considerably the larger of the two, being more prominent and more con- 

 vex, while the outer one is slightly concave transversely ; the intercondylar 

 notch is narrower than in Nothrotherium. On the proximal side of each 

 condyle is a small facet for the flabellae, which are large, irregular nodules 

 of bone. 



The patella (Plate XXXII, fig. 6, 6a) is most like that of Megalonyx, a 

 broad, shield-shaped bone, covered on the dorsal side with irregular lon- 

 gitudinal ridges, which give it a wrinkled appearance ; its distal portion is 

 more prolonged and ends in a much sharper point, while the articular sur- 

 face for the rotular groove, which is very slightly convex, has a relatively 

 greater proximo-distal extension. 



In its proportions the tibia (Plate XXXIII, fig. 3, 3*2) is intermediate 

 between that of Nothrotherium and that of Megalonyx ; it is considerably 

 shorter than the femur, and in relation to that bone is somewhat shorter 

 than in the former genus, longer and with narrower, less antero-posteriorly 

 compressed proximal end than in the latter; the facets for the femoral 

 condyles are separated only.by a narrow sulcus and the inner one is larger 

 and more concave and stands at a lower level than the outer, which is 

 convex and produced farther behind the plane of the shaft, though it has 

 no such extension as in Megalonyx, and the fibular facet is a longer, nar- 

 rower oval. The shaft is relatively longer, narrower and thicker than in 



