STERNAL RIBS OF HESPERORNIS. 67 



In the small number of sternal ribs articulating with, the sternum, 

 Hesjieromis resembles the Struthious birds, rather than the Natatores. The 

 persistent articulation of the uncinate processes with the vertebral ribs is 

 usual in birds incapable of flight, and has been observed in a few others. 



The following measurements show the principal dimensions of the 

 vertebral and sternal ribs, and uncinate processes in Sesperornis regalis. 

 The length of the vertebral ribs is measured in a straight line, joining their 

 extremities. 



Measurements of Vertebral Bibs. (No. 1206.) 



1st. 2d. 3d. 4th. 5th. 6th. 7 th. 8th. 9th. 



Length, in a straight line, 37. 83. .. 145. .. 172. 190. 209. __ mra 



Distance from center of head to 



center of tubercle, 23. 19. 19. 20. .. 20. 21. 21. 23. 



Elevation of tubercle, 10. 10. 8. 7. .. 4. 1. 0. .. 



Distance from tubercle to end of rib, 32. 83. .. 141. .. 159. 177. 194. .. 

 Distance of uncinate process from 



lower end of rib, .. 31. 35. 40. 52. 75. 



Measurements of Uncinate Processes. (No. 1206.) 



1st. 2d. 3d. 4th. 



Length, 25. 54. 52. 55. 



Diameter of articular end, 7. 12. 10. 11. 



Least breadth, 5. 11. 9. 8. 



Greatest breadth, 12. 15. 14. 15. 



Measurements of Sternal Ribs. (No. 1206.) 



1st. 2d. 3d. 



Length, .. 110. 



Diameter of proximal articulation, 9. 11. 9. 



Least antero-posterior diameter of shaft, 3. 5. 4. 



Diameter of distal articulation, 6. 8. 8. 



Diameter of distal end, 12. .. 15. 



5th. 



6th. 



50. 



30.' 



11. 



8. 



6. 



5. 



13. 



8. 



