ME. ST. GEORGE MIVART ON THE 



SACKUM OF A YOUNG RHEA. 

 Kg. 8. 



Lateral view (natural size). 



rl, diapophyses of 34th and 35th Tertebra; il, Uium; pa, large parapophysis of 27th vertebra; P, its articular surface for 



ilium; p, parapophyses of 34th and 35th Tertebrie; t, transTerse process of 33rd Tertebra. 



Ventral view (| natural size). 



at, autitrochanteric process ; il, ilium ; pa, parapophysis of 27th vertebra ; p, parapophyses of 33rd, 34th, and 35th vertebne ; 

 1, 2, 3, 4, and 5 indicate the 24th, 25th, 26th, 27th, and 28th yertebrce respectively. 



The twenfy-fifth vertebra (fig. 8, xxv, and fig. 9, 2) forms a part of the solid sacral mass. 

 A single large foramen is placed between its neural arch and that of its serial successor. 



The twenty-sixth vertebra (fig. 8, xxvi, and fig. 9, 3) exhibits no sign (as in the imma- 

 ture Struthio) of a union by suture of its neural arch with its centrum. Two super- 

 imposed foramina open, from the neural canal, between the neural arch of this vertebra 

 and that of the twenty-seventh. 



The twenty-seventh vertebra appears to answer to the thirty-first of Struthio ; but it 

 diflers from it in that it sends a larger truncated parapophysial surface (figs. 8 & 9, pa) 

 ventrad and postaxiad to abut against the preacetabular process of the ilium. This is 

 possibly, but not probably, formed (as in Struthio) partly by an adjacent preaxial para- 

 pophysial process of the twenty-eighth vertebra. Two small superimposed neural 



