ON A NEW SPECIES OF MACRAUCHENIA (M. BOLIVIENSIS) 415 
The narrower palate of the J/acrauchenia agrees with its narrower 
occiput, while it exhibits the same general correspondence with the 
Vicugna as has been met with in the limbs and vertebre. 
Thus I conceive that an attentive examination of these scanty 
remains is sufficient to prove that, when they were embedded, there 
lived in the highlands of Bolivia a species of Macrauchenia not half 
as large as the Patagonian form, and having proportions nearly as 
slender as those of the Vicugna, with even a lighter head ; and it is 
very interesting to observe that, during that probably post-pleistocene 
epoch, a small and a large species of more or less Auchenoid Mammal 
ranged the mountains and the plains of South America respectively, 
just as at present the small Vicugna is found in the highlands, and 
the large Guanaco in the plains of the same continent! 
The structure and geological date of the genus acrauchenia may 
serve, if taken together, to point an important paleontological moral. 
Professor Owen, in the able memoir cited above, has clearly pointed 
out the remarkable combination of Artiodactyle and Perissodactyle 
characters exhibited by Macrauchenia, which unites the eminently 
characteristic cervical vertebrae of the Artiodactyle Camelde with 
the three-toed fore foot and the triply trochantered femur of the 
Pertssodactyla ; and with an astragalus which, in the apparent entire 
absence of any facet for the cuboid, is, I may affirm, more Perisso- 
dactyle than that of any member of the order, except Ayrax. 
None of the older Tertiary mammalia can produce such strong 
claims to be considered an example of what has been termed “a 
generalized type” as Macrauchenia; and yet there seems little doubt 
that the latter is the South American equivalent, in point of age, of 
our Irish Elk! 
Again, Macrauchenia, alone, affords a sufficient refutation of the 
doctrine that an extinct animal can be safely and certainly restored 
if we know a single important bone or tooth. If, up to this time, 
the cervical vertebre of Macrauchenia only had been known, paleeon- 
tologists would have been justified by all the canons of comparative 
anatomy in concluding that the rest of its organization was Camelidan. 
With our present knowledge (leaving Macrauchenia aside), a cervical 
vertebra with elongated centrum, flattened articular ends, an internal 
vertebral canal, and imperforate transverse processes, as definitely 
characterizes one of the Cainel tribe as the marsupial bones do a 
Marsupial—and, indeed, better ; for we know of recent non-marsupial 
animals with marsupial bones. Had, therefore, a block containing an 
1 As the Guanaco ranges into the highlands, it may not be a too sanguine expectation to 
hope for the future discovery of remains of the great Aacrauchenda, also, in Bolivia. 
