PLATE XVIII. 



FIG. 



1. Numida meleagri^ (6 weeks old). 



2. Tinamus robustus" (adult). 



3. Tetrao cupido 3 (do.) 



4. Ornithorhynchus paradoxus* (adult). 



5. 

 6. 



7. 



Do. 

 Do. 

 Do. 



(do.) 

 (do.) 

 (do.) 



11. 



SIZE. 



Sternum ; side view . . nat. size. 



Sternum ; side view . . do. 



Furcula ; oblique view . . do. 



Shoulder-girdle and Sternum ; side 



view . . . . do. 



do. lower view do. 



Part of do. ; upper view . do. 



Ideal section of third sternal synovial 



joint . . .3 diam. 



Synovial surface of do. . . 200 do. 

 do. . .3 do. 



Part of Shoulder-girdle and Sternum ; 



lower view . . \\ do. 



Shoulder-girdle and part of Sternum ; 



side view . . . nat. size. 



do. lower view do. 



do. upper do. do. 



Front view of third sternal piece, 



with part of sternal ribs . 2 diam. 



1 See p. 184. 2 See pp. 185, 186. 3 See p. 184. 



* See pp. 192, 193. 5 See pp. 193, 194. 



8. Do. (do.) 



9. Do. (do.) 

 10. Echidna hislriaf* (half-grown). 



Do. (three-fourths adult). 



