214, “GIANTS’ BONES” IN PATAGONIA CHAP. 
the formula is the same as in 7'ypotherium. The animal seems 
to have had nails rather than hoofs. The thumb was opposable. 
The fibula is fused below with the tibia, whereas in the last 
genus these two bones are quite separate from each other. 
SUB-ORDER 5. TOXODONTIA 
The group Toxodontia,’ like so many others, is exceedingly 
hard to define. Nor are its limits any easier to mark out than 
many others of the groups of Ungulates. It will be best perhaps 
to give an account of Zowodon, and of a few types which seem to 
lie near it in the system, and then to indicate how far they 
resemble or depart in structure from other Ungulates. Toxodon 
itself is known from complete skeletons. It lived in Argentina 
during the “ Pampean ” period, which seems to be of the Pleistocene 
age. A large number of species, however, have been described, some 
of which seem to go farther back in time, and to have existed 
during the Miocene period further south in Patagonia. 
The size of this creature was about that of a large Rhinoceros ; 
it has a bulky body and a large head, which was borne low 
down, on account of the bending downwards of the anterior 
vertebrae; in this aspect the figures of the skeletons recall 
Glyptodon and similar Kdentates. The beast was discovered by 
Darwin, and originally described by Owen. “ During his (Mr. 
Darwin’s) sojourn in Banda Oriental,’ writes the Rev. H. 
Hutchinson, “having heard of some ‘giants’ bones’ at a farm- 
house on the Sarandis, a small stream entering the Rio Negro, 
he rode there, and purchased for the sum of eighteenpence the 
skull which has been described by Sir R. Owen. The people at 
the farm-house told Mr. Darwin that the remains were exposed 
by a flood having washed down part of a bank of earth. When 
found, the head was quite perfect, but the boys knocked the teeth 
out with stones, and then set up the head as a mark to throw 
at.” The whole of the Pampean area is a valley of dry bones, 
and the remains of Zoxvodon are abundant there. The skull of 
Toxodon is not unlike that of a horse in general aspect; but the 
orbit is not separated from the temporal fossa. The premaxillae 
are furnished above with a slight protuberance directed towards 
' Cope, American Naturalist, xxxi, 1897, p. 485. 
