342 



PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



MEASUREMENTS. 



Ulna, length 344 



" " of olecranon 062 



" width at sigmoid notch 056 



" distal width 020 



" " thickness 019 



Metacarpal I, length 038 



" " proximal width 022 



" " distal width 017 



Metacarpal II, length 064 



" " proximal width 023 



" " distal width 027 



Metacarpal III, distal width 026 



Metacarpal IV, length 089 



Metacarpal IV, proximal width 028 



" " distal width 025 



Phalanx i, digit I, length 030 



" " " " proximal width 018 



Phalanx I, digit II, length. 028 



" " " " proximal width ... .025 

 Phalanx 2, digit II, length 047 



" " " " proximal width ... .021 

 Phalanx 2, digit III, length 043 



" " " " proximal width ... .026 



Ungual, digit I, length 045 



Ungual, digit III, length 085 



" " " proximal width 023 



The pelvis is represented by imperfect specimens, which give no infor- 

 mation upon certain important questions, yet are sufficiently complete to 

 show a number of significant differences from the pelvis of Hapalops. 

 The ilium has an even shorter peduncle than in the latter ; its anterior end 

 is somewhat more expanded and everted and has a more definite and 

 thickened crista. The dorsal portion of the ischium is less horizontal and 

 extends upward as a broad, thin plate, which is ankylosed with the trans- 

 verse processes of the last two sacral vertebrae ; the tuberosity is not very 

 large, yet more prominent than in Hapalops; the descending portion is 

 very long, quite broad and very thin, making the obturator foramen 

 large, with dorso-ventral diameter much exceeding the antero-posterior, 

 and giving the posterior pelvic opening a remarkably large dorso-ventral 

 diameter. The pubis is long and very slender, except distally, where it 

 expands to take part in the symphysis, which is quite elongate. The 

 resemblance of this pelvis to that of Megatherium is quite distinct. 



The femur (text-figure 25", p. 1 73 ; Plate LX, fig. 8) is remarkable for 

 its great breadth and antero-posterior compression ; its general appear- 

 ance and proportions are quite like those of Megalonyx, but there are 

 certain suggestive similarities to Megatherium. The hemispherical head 

 is very large, and the large pit for the round ligament, which is on the 

 posterior side, is entirely enclosed in the articular surface; the neck is 

 longer than in Megatherium and the bridge from head to great trochanter 

 is longer and has a more concave border. The great trochanter is very 

 large and massive and encloses a considerable digital fossa; the second 

 trochanter differs from that of the Pleistocene genera in being a prominent, 



