ii.s 77//; .\.\n:ni('.\.\ .i/r.s/.r.i/ joiuxal 



impossihility to an animal the si/c of the Mi ijuIIk riinii. It could not have 

 been oilier than tcrfcst rial or a(|natic, an<l of the latter mode of life there is 

 no indication in its structure. 



In his hrilliant and masterly argument the ;^q-eat iMijilish anatomist 

 showed how the teeth were adaj)te(l to the hruisin^c ;iiid crushing of leaves 

 and twiij;s, how tlie structure of the jaws and skull and arrangement of the 

 ner\c channels indiciited loose, flexible lips and long prehensile tongue 

 adapted to browsing; how the long loose-jointed forelinibs would enable 

 it to lay hold of branches or small trees and drag them down within reach; 

 how the powcrfid claws would enable it to dig around the roots of larger 

 trees and loosen them, and the massixc hind (|uarters and tail would give 

 the necessary weight and fulcrum to pull down these trees when loosened 

 in order to feed upon the upper foliage thus brought within its reach. In 

 incidental support of this theory, he pointed to the fre(|uent occurrence of 

 fracttu'cs in the massixe, hea\y bones of limbs and skidl. One of the 

 skeletons in this group has a naturally healed fracture of the bones of the 

 hind leg very likely due to a tree falling upon it in the course of its lumbering 

 operations — lumbering, perhaps, in more senses than one. 



Such is the theory of the habits of life of the ground sloths, which this 

 group is designed to illustrate. As to their appearance, we know from 

 recent discoveries that the Mi/hnlons were covered with a thick coat of 

 furry hair, somewhat like the brown bears of Alaska. A large piece of the 

 hide found in a cavern at Last Hope Inlet, Patagonia, is preserved in the 

 British Museum. It is of a golden brown color, and the thick skin, 

 in which are buried numerous small nodules of bone, made an effective 

 defense against cold, the assaidts of nearly all beasts of prey, and most of 

 the bumps and bruises incidental to its mode of life. The one carnivorous 

 enemy the Mi/Jodon might have cause to fear would be the great sabre- 

 tooth tiger, SniilodoH, whose huge compressed canine tusks and powerful 

 organization were adapted to prey ui)on the great thick-skiimed groimd 

 sloths and other large herl)ivora. 



The (iround Sloth Groiij) is the most realistic that has yet been at- 

 tempted in the moimting of fossil skeletons, and the metiiod of moimting, 

 eliminating the ujjright steel rods ordinarily used, adds much to its elVective- 

 ness. This method, (le\"ised in H)()4 l)y .\lb(>rt Thomson of this depart- 

 ment, is here applied for the first time by Head Prepjirator Hermann to the 

 mounting of large skeletons. The group was designed by Erwin Christman 

 and a small working model made. The parts of th(^ skeleton in the model 

 are easily a(ljustal)le. and the poses were criticised and discussed in com- 

 parison with the unmounted skeletons by Professor Osborn and the scientific 

 staff until an adjustment was reached which seemed to rej)resent the most 



