XIII 



PHYLUM CHORDATA 



383 



keel is vestigial or absent. The coracoid and scapula are com- 

 paratively small and completely ankylosed ; the acrocoracoid pro- 

 cess is vestigial, and the coraco-scapular angle approaches two right 

 angles. The wing is reduced in size and may be vestigial or absent. 

 There are large basi-pterygoid processes developed from the basi- 

 sphenoid. The vomer is large and broad. The quadrate articu- 

 lates with the skull by a single or partially divided facet. The 

 male has a penis. The young are precocious. 



FIG. 992. Apteryx aus trails, with egg. (From a specimen in the Royal College 

 of Surgeons, London.) 



**** .ORDER 1. MEGISTANES. 



Including (a) the Emus (Dromceus) and Cassowaries (Casuarius),. 

 (b) the Kiwis (Apteryx, Fig. 992), and (c) the Moas (Dinornithidce 

 Fig. 1007). 



ORDER 2. RHE.E. 

 Including the South American Ostriches (Rhea\ 



