X 



AXIAL SKELETON OF THE STEUTHIONIDJE. 



neural spine is excavated, but not obliquely so, at each end. The ventral angles of the 

 postaxial central articular surface are more drawn out than in the preceding vertebrae, 

 or than in the sixth vertebra of Struthio. 



The seventh vertebra. — All that has been said of the seventh vertebra of Struthio 

 applies to that of Ehea, except that in the latter the rib is rudimentary, and the neural 

 spine is much smaller. 



The eighth, ninth, and tenth vertebrae also agree with those of Struthio, except that 

 the neural spine is hardly excavated in the eighth, and ia the others only behind, and 

 that the ribs are rudimentary— although the pleurapophysial continuation of the para- 

 pophysis projects much more preaxiad than does the prsezygapophysis, which is not the 

 case in Struthio. 



ELEVENTH VERTEBEA OF BHEA (natural size). 

 Fig. 6. - Fig. 7. 



Fig. 6. Postaxial view. 



Fig. 7. Lateral view. 



Letters as before (see p. 3), except that c denotes the catapophysis, m the metapophysis, J3 the 

 parapophysis, andjjs the rudimentary rib. 



The eleventh vertebra. — This appears more or less to replace the eleventh, twelfth, 

 and thirteenth vertebrte of Struthio. It is very like its predecessor, but is slightly more 

 massive. Its neural spine is grooved above, the groove widening postaxially. The prse- 

 zygapophysis projects but very slightly, if at all, preaxiad of the most preaxial part of 

 the pleurapophysis. The ventral angles of the postaxial central surface are much 

 drawn out (fig. 6) ; and thus (unlike Struthio) its ventral margin is greatly in excess of 

 its dorsal margin, the ventral surface of the centrum being very concave transversely. 



The twelfth vertebra seems to answer to the thirteenth and fourteenth vertebrae of 

 Struthio, and differs from its predecessors as does the fourteenth vertebra of the Ostrich 

 from its predecessors. Unlike the fourteenth vertebra of Struthio, however, it is still 

 rather slender (pre- and postaxially lengthened), and the ventral angles of the postaxial 

 surface of the centrum are greatly drawn out. 



