xiv.] EDENTATA. 261 



united extremities of the acromion (a) and coracoid (^), and 

 internally by the intervention of a long fibre-cartilaginous 

 " omosternum " (degenerating into a mere ligament in the 

 adult) to the presternum. In Bradypus the clavicle is very 

 small, and separated by a long interval from the sternum. 

 It originally articulates at its scapular end, as in Cholapus ; 

 but in consequence of the atrophy of the acromion, it is 



FIG. 83. Right scapula and clavicle of Two-toed Sloth (Cholafius hoffntanm), i\. 

 af prescapular fossa ; />/ postcapular fossa ; %c glenoid cavity ; a acromion 

 c coracoid ; / coraco-scapular foramen ; cl clavicle. 



left attached to the end of the coracoid, in which unusual 

 situation it remains through adult life. 



In the MARSUPIALIA the scapula is tolerably uniform in 

 shape. The acromion is long, and the coracoid small, of a 

 somewhat hooked form, and thick at the base. It ossifies 

 by a separate endosteal nucleus. 



The clavicle is present in all known Marsupials except 



