Mo*t of the HtVH are anobliieraied : the post fron tab art distinct bones : the prelrnntals 

 are roiinair. wid derelope brad external cranial plate between the fruuuli and iuual. Thr 

 occipital esHBcat* haw coalesced. 



Prttenfrd by Ike Zoological Society of London. 



Genus Rkea. 



1361. The skeleton of the Three-toed Ostrich (Rkea .////<, ,,,/,/a). 



* The sternum hat a single median notch posteriorly . The rlavicln are absent, and are indi- 

 cated only by an unusual developrm-ut of the acromion scapulte. The Kapula and coracoid 

 have coalesced, at in the Emeu. The iachia are united to each other along the greater part 

 of their extent, at alto to the ilium above and to the pubit below. The wing u more deve- 

 loped than iu the Knu-u, mid the metacarpus consisU of the uiiual three auchylosed bone* 

 supporting the common number of modified phalanges in birds. There are 22 vertebrae be- 

 tween the tkull and tacrum, of which the last seven tupport ribt : tin- Aral two pairs an- free , 

 the next three pain articulate by bony hsemapuphyie* with the sternum ; the but three pair* 

 of ribt are free, and of these the last (eighth) pair belong to the first of the auchylosed or 

 sacral vertebrae. There are 6 caudal vertebrae. 



Mint. Soxtk. 



Geous SlmtJtio. 



IV skeleton of the Ostrich (Hint km Cornelia). 



The sternum hat two posterior emarginations and a cartilaginous xiphiitemal, which i* 

 sornetimes the seat of a distinct ossification. The coracoid hat coalesced with the scapula. 

 and ossification hat extended along the ligamentou* or fibro-cartilaginoiu basis of the ela- 

 viclet, to that these bones appear at strong acromial prooettet coalescing at their inner ex- 

 tremity with the coracoid, and leaving an elliptical t|iace between them and that bone : the 

 isehium hat coalesced posteriorly with tin- pubu on each gide, but the nymphysis pubis, whirh 

 it peculiar to this bird, is still cartilaginous. Although but two toes are developed, the third 

 metatanal b present, coalesced at usual wjth the two belonging to the toes ; but it terminate* 

 below in a short pointed procesf, at the inner tide of the trochlea supporting the larger Uie. 

 This toe it shown by the number of iu phalanges (four) to answer to the middle in the tri- 

 dactyle Ostrich, and the second, although the shorter toe, hat the the phalanges character- 

 istic of the outer toe. The inner (or second) toe and the back toe (first) are wanting in the 

 Ostrich : both are present in the Aptrryx. There are 25 vertebra? between the tkull and 

 sacrum, of which the last seven support ribs : the first two pairs are free ; the succeeding five 

 |iairt are articulated to the sternum by strong bony hspmapophyses ; the hut (eighth) pair of 

 ribt are attached to the sacrum, and terminate freely. There are 7 caudal vertebrae. 



Jluativta* 



