16 



strong, assists in supporting, rather than depends from the broad sacral temaina- 

 tion of the pelvis. 



The sacrum is lengthened at the expense of the lumbar vertebrae by a continua- 

 tion of the general anchylosis through that region. 



A long and capacious thorax is defended by sixteen pairs of ribs, most of which 

 equal in breadth those of the Elephant, and all the true ribs are clamped by 

 massive and completely ossified cartilages to a strong and complicated sternum. 



The scapulae, distinguished by their unusual breadth, and by the osseous arch 

 connecting the acromial and coracoid processes, are attached to the large manu- 

 brium sterni by strong and complete clavicles. 



The humeri, short and thick, like the femora, have their muscular processes, 

 ridges and condyles still more strongly developed ; but the rotatory and lateral 

 movements are unobstructed by any inordinate production of the proximal 

 tuberosities. 



The fore-arm is longer than its corresponding segment in the hind limb, has 

 both bones distinct, and equally remarkable for their great breadth and the an- 

 gular form occasioned by the prominence of the intermuscular ridges ; yet the 

 mechanism for free pronation and supination is complete . 



The fore-foot is pentadactyle, but so unusually massive are the proportions of 

 the radius and ulna, that, though actually broad and thick, it appears relatively 

 small ; and notwithstanding certain fingers are terminated by claw-bones of great 

 size and length, yet owing to the form of their proximal phalanges and meta- 

 carpal bones, it is short in proportion to its breadth. 



The hind-foot is tetradactyle, with the two inner toes elongated and armed 

 with unequal but large claws. 



Both the fore- and hind-feet are remarkable for the shortness, breadth, and 

 ungulate character of the two outer digits, which, when the Mylodon stood or 

 trod upon the ground, must have principally sustained the superincumbent 

 weight. 



A skull, smaller than that of the Ox, but long, narrow and terminated by a trun- 

 cated muzzle, is supported by a short neck composed of seven cervical vertebrae. 



These vertebrae are freely articulated together, and are succeeded by sixteen dor- 

 sal or costal vertebrae, remarkable for their broad and high spinous processes, 

 which are nearly equal, and have an uniform incUnation backwards. 



