406 ON A NEW SPECIES OF MACRAUCHENIA (M. BOLIVIENSIS) 
The muscular ridges on the posterior face are as well marked as in 
the skeleton of the Guanaco, and far more distinct than in that of 
the Vicugna, yielding additional evidence of the adult condition 
of the animal, to that afforded by the absence of epiphyses. 
The antero-posterior diameter of the tibia, measured from the 
posterior edge of the internal articular facet to the anterior edge of 
the crest of the tibia, is, in— 
Jf. Boltviensis. a, Patachonica. Guanaco. Vicugna. 
in. in. in. in. 
24 54 25 mi, 
so that the depths of the proximal ends of the tibie of the two 
Macraucheni@ have the ratio of 1:21, which corresponds very well 
with the proportions of the astrega.i, and confirms the conclusions 
already arrived at, as to the rélaciv2 “izatness of the limbs of this 
species in comparison with of LW SF rtiwcdonica, and as to the 
similarity of the proportions :7 ite Ecli-can species to those of the 
Llamas. 
What remains ¢! the outs: 2¢5= of a ubia is sufficient to prove 
that the fibula must hive remicec uranchylosed to the tibia for a 
iiuch: greater distascs “ss Se Se "aca conian species. From the 
manner in which the cites tizerosic or the proximal end of the 
tibia is broken on. I am iachced to sesvect that the fibula was 
anchylosed to it at ths ean and vertags, as in the tuchenze, its 
proximal end was represe siv Dv a bonv strle. 
The scapula is represented mere.» by i mutilated fragment, com- 
prising the glenoid cavity and the — sarts. The spine of the 
scapula is broken off, and the glenvid cavity is somewhat distorted 
by the bending of one of its edges; but enough remains to show 
that the bone must have agreed with the scapula of Vacrauchenta 
Patachonica in all essential respects, and that it therefore differed 
very widely from that of the duchenic. In size, however, it nearly 
corresponded with the corresponding bone in the latter animal ; for 
the greatest diameter of the glenoid cavity is 1-2 inch, the same 
measurement in the Vicugna being to, and in the Guanaco 16. 
The ulna—The fragment of the ulna, consisting of part of the 
olecranon process and of the sigmoid cavity, is so crushed, that 
I can only affirm its general agreement in form with that of 
Macrauchenia Patachonica, and in size with the same bone in the 
Llamas. 
The lumbar vertebra—Of bones referable to this region of the 
body, again, there is but a single fragment, of value only so far as it 
