IG 



ANATOMY OF VERTEBEATES. 



vertical lamina3 towards the sacral region {Ajitenodytcs, Catar- 

 rhactes) ; but, in the Ostrich, the bodies of the dorsal vertebra) 

 retain their breadth throughout the series. 



The bodies are united by capsular ligaments and synovial mem- 

 branes; the anterior articular cartilaginous surface is convex in 



14 



Skeleton of Flamingo. A. Corax Mitis. 13. Tinamou (T. ro&Hs«Hs). C. Plicenicopterus. 



the vertical direction, and concave in the transverse ; the posterior 

 surface is the reverse. The Penguins and Auks, however, present 

 an exception to this rule : the posterior surface of the second or 

 third dorsal vertebra is concave, to which the opposed end of the 

 succeeding vertebra presents a corresponding convexity ; the 

 ' opisthococlian ' ball-and-socket-joint is continued between the 

 centrums to the last dorsal.^ In many Birds the bodies of some of 

 the middle dorsal vertebra3 are anchylosed together ; and in gene- 

 ral those which are nearest the sacrum. In the Flamingo, fig. 



' VII. p. 270, and x. pi. 52, figs. 50, 51. 



