366 
PROFESSOR OWEN ON THE MEGATHERIUM. 
Another important evidence of the affinity of the Megatherium to the Sloths was 
brought to light by a fragment of the skull from Punta Alta, which demonstrated a 
fifth small molar tooth on each side of the upper jaw, thus showing that in the 
number as well as in the structure and the kind of teeth the Megatherium agreed 
with the Bradypodidoe, and especially with the Ai or Three-toed Sloth ; the anterior 
pair of molars not manifesting the excess of size and laniary form which characterize 
them in the Unau or Two-toed species*. 
These additional evidences of the concordance of structure between the Mega- 
therium and the Sloths, manifested by the hard and enduring parts which are most 
intimately related to the food of the animal, induced me to reconsider the conclu- 
sions of Cuvier, Pander and D’Alton, and Dr. Buckland relative to the sources of 
its nutriment and its habits of life ; and ultimately to arrive at a conviction of the 
correspondence of the food of the Megatherium with that of the Sloths, and of the 
relation of the modified form of the Megatherium to its peculiar mode of obtaining 
such food, the grounds for which conviction are given in my memoir on the 
Myludon rohnstus, published in 1842. 
By the analogy of this smaller species of the great extinct terrestrial Sloths of 
South America, I endeavoured to dissipate some of the doubt and obscurity which 
shrouded the true structure of the fore and hind feet of the Megatherium-|' ; but the 
light so obtained served rather to increase the desire to inspect the skeleton itself at 
Madrid, and obtain, ex visu, a conviction of the accuracy of my views ; for I partici- 
pated entirely in the doubts expressed by my experienced colleague Mr. Clift:|: 
relative to that skeleton, then unique in Europe, viz. as to “ whether it had been 
properly or improperly mounted, i. e. whether all the parts were of one or more indi- 
viduals, whether they belong to the situation or position in which they are placed, 
whether all the parts are genuine or partly modelled, or whether parts are eked out 
by bones that do not belong to the part or situation in which they are collected 
concurring at the same time vvith Mr. Clift, that ‘‘no blame was attributable to the 
articulator, who, probably, had little or no guide in such a difficult task.” 
Year after year, however, passed away without bringing with it the requisite liberty 
from official duties for a visit to Madrid. I availed myself of the rare opportunities 
alforded by journeys of scientific friends to that city to endeavour to obtain informa- 
tion on some of the discrepant or doubtful points, and more especially relative to 
the exact number of teeth or sockets of teeth in the skull ; but usually without any 
satisfactory result, owdng chiefly to the difficulty which the mode of preserving the 
famous skeleton presents to any close inspection. Dr. Daubeny, the accomplished 
Professor of Botany at Oxford, in reply to one of my requests, wrote to me from 
Madrid: — “I have examined the Megatherium and can discern only four teeth in 
* Zoology of the Voyage of Her Majesty’s Ship ‘ Beagle,’ Fossil Mammalia, 4to, 1838—40, p. 102, 
■f Description of the Skeleton of the Mylodon robustus, 4to, pp. 102, 131-136. 
I “Notice on the Megatherium,” Geol. Trans. Second Series, vol. iii,, description of plate 44. 
