$ MR. ST. GEORGE MIVART ON THE 
SACRUM OF A YOUNG RHEA. 
Fig. 8. 

Lateral view (natural size). 
d, diapophyses of 34th and 35th vertebra ; il, ilium; pa, large parapophysis of 27th vertebra; P, its articular surface for 
ilium; p, parapophyses of 34th and 35th vertebre; ¢, transverse process of 33rd vertebra. 

Ventral view (3 natural size). 
at, antitrochanteric process; iJ, ilium; pa, parapophysis of 27th vertebra; p, parapophyses of 33rd, 34th, and 35th vertebrex ; 
1, 2, 3, 4, and 5 indicate the 24th, 25th, 26th, 27th, and 28th vertebra respectively. 
The twenty-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, xxv, 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 ¢wenty-seventh vertebra appears to answer to the thirty-first of Struthio; but it 
differs 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 
