arguments from the skeleton in addition to those of which Dr. Buckland had pre- 

 viously availed himself, simply affirming that " the Megatherium is proved to have 

 been certainly covered by an osteo-dermal carapace, by the disposition of the spinous 

 processes of the vertebrae, by the angles of the ribs, by the articulation of the pelvis 

 with the vertebral column," &c. ; and he concludes by announcing "that the Mega- 

 therium was a gigantic species of Armadillo, most nearly allied to the diminutive 

 Chlamyphorus *." 



With regard to the fossils from South America, unequivocally referable to the 

 Armadillo family, I had myself pointed out the generic distinction of that large 

 quadruped, some bones of which had been transmitted along with the gigantic der- 

 mal armour by Sir Woodbine Parish, and proposed for it the name of ' Glyptodon ' 

 in Sir Woodbine Parish's work on Buenos Ayres -f-; and afterwards, stimulated by 

 the general tendency of anatomists and palaeontologists to regard the Megatherium 

 as being, likewise, a gigantic Armadillo, I entered upon a critical review of all the 

 facts of the case which at that time had been obtained, and communicated the result 

 in a memoir to the Geological Society, read March 23, 1839 J. The general con- 

 clusions from this memoir were: — 



1. The opinions of Cuvier and Weiss, in favour of the Megatherium being so 

 armed, rest on no better ground than the mere fact of bony armour of some gigantic 

 quadruped and the skeleton of the Megatherium having been discovered in the same 

 continent. 



2. The skeleton, or its parts, which have been actually associated with the bony 

 armour above mentioned, belongs to a quadruped distinct from and less than the 

 Megatherium. 



3. No part of the skeleton of the Megatherium presents those modifications which 

 are related to the support of a dermal covering. 



4. The proportions of the component tesserae of the bony armour in question to 

 the skeleton of the Glyptodon are the same as those between the dermal tesserae and 

 skeleton of existing Armadillos, but are much smaller as compared with the bones of 

 the Megatherium. 



5. No bony armour composed of tesserae having the same relative size to the bones 

 of the Megatherium as in the Glyptodon and existing Armadillos, has yet been dis- 

 covered. 



In 1837 I had been put in possession of an additional test of the affinities of the 

 Megatherium, by portions of teeth, obtained by Mr. Charles Darwin at Punta Alta 

 in Northern Patagonia, from which specimens I was kindly permitted to take the 

 requisite sections for microscopical examination. Previous researches by Professor 



* " Recherches sur l'anciennete des Edentes terrestres a la surface de la terre," Comptes Rendus de l'Acad. 

 dea Sciences, 1839, p. 65. 



t P. 178 A, frontispiece, 8vo, 1838. 



{ " On the Glyptodon clavipes," Transactions of the Geological Society, second series, vol. vi. p. 98. 



B 



