FROM CENTRAL AND SOUTH AMERICA. 
561 
vidual was obtained from one of the caves, which proved to be identical with that pre- 
viously found, in the Sumidouro cave, associated with human bones” (p. 89). And we 
are enabled to judge of an instructive character of this Equine by the figure of the 
grinding-surface of the fourth molar, right side, upper jaw (“Fjerde Kindtand i ho'ire 
Oberkjaeve,” p. 93, (1Y.) tab. xlix. fig. 2). 
This figure, to which I have added the symbols of characteristic parts of the grinding- 
surface used in my preceding memoir, is reproduced in fig. 12, Plate LXII., for the 
purpose of comparison with the type specimen of Equus curvidens , fig. 2, Plate LXI. 
Of the difference of Lund’s Equus aff. caballo from his Equus neogoeus and Equus 
■principalis, the figures of the grinding-surface of the molars given in his tab. xlix. figs. 
1 & 3 (figs. 9 & 10, Plate LXII.) leave no doubt. These specimens, Dr. Lund says, 
were extracted “from very old breccia”*. Without entering into any descriptive detail 
or comparison of them (which, indeed, would have been barely if at all available in the 
absence of the requisite descriptions and figures of the teeth of known species of Equus), 
he remarks, thatf il Equus neogceus is more remote in the formation of the teeth from 
the common form of Horse than Kaup’s Hippotherium ; and since that animal already 
shows such essential deviations from the single-hoofed form in the structure of the feet, 
it is to be presumed that Equus neogceus, when it is better known, will present still more 
considerable deviations. This is even more the case with Equus principalis, which, to 
judge from its deviating form of tooth, may well have possessed extremities as different 
from those of the Horse, as those animals which we, with Owen, have learned to recog- 
nize as Macrauchenia, or, in other words, may be the same animal:” 
Leaving, for a while, this question, I will merely now remark that, through Dr. 
Lund’s discoveries of at least one kind of horse remarkably distinct from any existing 
species, and, I may add, any known European fossil Equine, all reasonable doubt as to 
that form or family of perissodactyle Ungulate having coexisted with Megatherium &c. 
in pliocene or postpliocene time, in South America, was set at rest. 
Passing to the Equus aff. caballo , Lund, its discoverer, in reference to the association 
of its remains with those of Man, speculates as to “ whether it may have been used by the 
inhabitants in those remote times as a domestic animal. It may,” he proceeds, “ easily 
be supposed possible to solve this question by a simple examination of the remains of 
the animal; but it will in all cases require a comprehensive comparison of a large 
number of specimens, since one of the results of domestication is to enlarge the limits 
for the play of individual variation. Upon the small number of specimens I have had 
* “ Der ikkim forekomme i meget gamle Breeder, ” (IV.) tom. xii. p. 89. 
t “Thi Equus neogceus fjerner sig i Dannelsen af Teenderne meget mere fra den almindelige Hesteform, 
end Kattp’s Hippotherium, og da dette Dyr allerede udviser saa vsesentlige Afvigelser fra Eenhoverformen i 
Bygningen af Fodderne, er det at formode, at Equus neogceus, naar den bliver bedre bekjendt, vil frembyde 
endnu betydeligere Afvigelser. Dette gjelder endnu mere om Equus principalis, der efter sin afvigende Tand- 
form at sluttc, meget vel kunde have besiddet Extremiteter saa forskjellige fra Hestens, som de, vi ved Owen 
have lsert at kjende for Macrauchenia, med andre Ord, vasre det samme Dyr.”— Op. cit. p. 90. 
