384 Mr. C. W. Andrews on the Skull, 



The dimcusions (in millimetres) of the sternum are : — 



mm. 



Length in middle line 47 



Width between tips of antero-lateral processes 



about 23.5 

 Width between tips of postero-lateral processes 



about 280 

 Length of lateral borders (between end of 



autero- and postero-lateral processes) 125 



Distance between inner end of coracoid grooves 66 



Length of coracoid groove 60 



It may be remarked that the right half of the specimen 

 (left in the figure) has been much flattened^ so that the 

 measurements of the width, both at the anterior and pos- 

 terior ends, as given above, are somewhat too great, and the 

 same distortion is the cause of the want of symmetry seen in 

 tlie figure. 



Comparison of the sterna of Strut hio, Rhea, Dromeeus, 

 and Casuarius with the fossil shows that they diflFer from it 

 in almost every structural feature, as well as in the relative 

 proportions of their length and breadth. In Rhea, however, 

 the coracoids are separated from each other by a consider- 

 able interval, though a much smaller one than in ^pyornis, 

 and the border between them is concave; in Casuarius and 

 Dromaus there are four rib-facets. 



The sterna of the New Zealand Ratitse show a much greater 

 resemblance to that of y^pijornis, although the various forms 

 occurring among the Dinornithidse are still very different, par- 

 ticularly in the straight or convex anterior border, the position 

 of the pneumatic foramina, the absence or very rudimentary 

 condition of the coracoid impressions, and the greater deve- 

 lopment of the xiphisternal region. On the other hand, the 

 distance of the coracoid impressions from one another, and, 

 in Pachyornis, the posterior divergence of the lateral borders 

 and the great width in proportion to the length, are points 

 of similarity. 



It is in the sternum of Ajjteryx, however, as Milne- 



