20 
EXPLANATION OF PLATES 6. 7. 
12, 13. Armour, supposed to be that of Megatherium.* 
14 19. Armour of Dasypus and Chlamyphorus. 
Plate 6. V. I. p. 148. 
1. Sections of Teeth of Megatherium, illustrating the 
relative dispositions of the Ivory, Enamel, and Crusta 
petrosa, or Coementum. (Original. Clift.) 
2. Posterior surface of a caudal vertebraof Megatherium, 
exhibiting enormous transverse processes. On its 
lower margin are seen the articulating surfaces 
which received the chevron bone ; the superior 
spinous process is broken off. V. T. p. 151. (Sir 
F. Chantrey. Original.) 
Plate 7. V. I. p. 168. 
Ichthyosaurus platyodon from the Lias at Lyme Regis, 
discovered by T. Hawkins, Esq. and deposited in. the Bri- 
tish Museum, together with all the other splendid fossil re- 
mains that are engraved in his memoirs of Ichthyosauri 
and Plesiosauri. This animal, though by no means full 
grown, must have measured twenty-four feet in length. The 
extremity of the tail, and left fore paddle, and some lost 
* Mr. Darwin has recently discovered the Remains of Mega- 
therium along an extent of nearly six hundred miles, in a North and 
South line, in the great sandy plains of the Pampas of Buenos Ayres, 
accompanied by hones and Teeth of at least five other Quadrupeds. 
He has also found that the Bones of this Animal are so often accom- 
panied by those of the Mastodon angustidens, as to leave no doubt 
that these two extinct species were contemporai-y. 
I learn from Professor Lichstenstein, that a fresh importation ol 
Bones of Megatherium, and bony armour has lately been sent to 
Berlin from Buenos Ayres, and that there remains no room to doubt 
that some portion of this armour appertained to the Megatherium. 
It appears very probable, from more recent discoveries, that 
several other large and small animals, armed with a similar coat of 
mail, were co-inhabitants of the same sandy regions with the Mega- 
therium. 
