MEGATHERIIDA 185 
of this family may be conveniently designated, agree with the 
Sloths and Anteaters, and thereby differ from all other mammals, 
in that the coracoid process of the scapula and the coracoidal 
border of the same unite over the coraco-scapular notch, 
which is thus converted into a foramen. Large clavicles are 
present. 
Megatherium..cThe typical genus Megatherium, as being the 
longest known representative of the family, may be noticed in some 
detail. A nearly complete skeleton, found on the banks of the 
River Luxan, near Buenos Ayres, and sent in 1789 to the Royal 
Museum at Madrid, long remained the principal if not the only 
source of information with regard to the species to which it belonged, 
and furnished the materials for many descriptions, notably that of 
Cuvier, who determined its affinities with the Sloths.2 In 1832 an 
important collection of bones of the Megatherium was discovered 
near the Rio Salado, and secured for the Museum of the College 
Fic. 61.—Oral surface of mandible of Megatherium americanum. 
a, Condyle ; b, masseteric process; c, angle; d, symphysis. (After Owen.) 
of Surgeons of England ; and these, with another collection found 
at Luxan in 1837, and now in the British Museum, supplied the 
materials for the complete description of the skeleton published 
by Sir R. Owen in 1861. Other skeletons have subsequently been 
received by several of the Continental museums, as Milan and Paris, 
and also by those in South America; and consequently our know- 
ledge of the organisation of the Megatherium, so far as it can be 
deduced from the bones and teeth, is as complete as that of any 
other animal, recent or extinct. 
The remains hitherto spoken of are all referred to one species, 
Megatherium americanum of Blumenbach (Jf. cuviert of Desmarest), 
and are all from the newest or Pleistocene geological formations of 
the Argentine Republic and Paraguay, or the lands forming the 
1 Cuvier, Tableaw Elém. d’ Hist. Nat. des Animaux, p. 146 (1798). 
? An excellent figure of this skeleton, which unfortunately was incorrectly 
articulated, and wanted the greater part of the tail, was published by Pander 
‘and D’Alton in 1821, and has been frequently reproduced in subsequent 
works. 
