Observations on the Anatomy of the Sloth. 501 



These discrepancies will appear more evident, being placed 

 in a tabular form. In the first column we have arranged Cu- 

 vier's adult specimen, in the second our own. 



Cuvier. 



45 43 



The transverse processes of the first caudal vertebra, are 

 elongated, and flattened or depressed, and are united to the 

 OS ischium by cartilaginous suture, which tends very much to 

 enlarge the capacity of the pelvis, the outlet of which is dispro- 

 portionably large : the posterior, or sacral region, presents a 

 very broad, nearly flat, and solid surface, for the pregnant ute- 

 rus to rest upon, as well as to accommodate the enormous rec- 

 tum, in the usual position of the animal ; that is, suspended from 

 the lower surface of the limbs of trees, the back towards the 

 earth : by this form of the pelvis, the cotyloid cavities, and con- 

 sequently the thigh bones are widely separated, rendering an 

 approximation of the knees difficult ; an arrangement, which 

 though exceedingly inconvenient to a quadruped walking on 

 the ground, is, at the same time, an admirable structure for an 

 animal always embracing a trunk, limb, or some foreign body, 

 between his thighs. The ossa pubis are separated more than an 

 inch, by an intervening cartilage in the present instance, which 

 was ossified in Cuvier's specimen ; whilst the sacro-ischiatic 

 ligaments, uniting the sacrum to the ischium at the suture be- 

 tween the tuber ischii and transverse processes of the first cau- 

 dal vertebra, are already ossified. The sternum is composed 

 of nine distinct pieces ; its nine cartilages are all ossified, and 

 united to the true ribs and sternum by cartilaginous suture : the 

 ninth cervical vertebra supported at the extremity of the trans- 

 verse process, an osseous rudiment of a rib, to which it is joined 

 by cartilage : the unusually long neck of this animal, was ex- 

 ceedingly flexible, particularly so in the anterior direction, form- 

 ing very readily a complete circle, with the snout resting on the 

 ninth vertebra. This long and flexible neck, bending in every 



