156 On the Tarsus and Carjnis of Birds. 



Fig. 18. Spizella socialis. 

 19. 



20. " " 



21. Turdus fascescens. 



22. Molotltrus pecoris. 

 23.- Tyran7ius Carolinensis. 



24. Dendroeca mstiva. 



25. Qidscalus versicolor. 



26. Tringoides mamdarius. 



27. Ootyle riparia. 



'^^' " " Several days from the egg. 



29. Tringoides maadariits. just read}^ to hatch. 



30. Hirundo lunifrons. 



31. Sialia sialis. 



EXPLANATION OF LETTERS. 



FE. Femur. 



T. Tibia. 



F. Fibula. 

 f t. Tibiale = astragalus. 

 TARSUS. <( f' Fibidare = calcaneum = o.s calcis. 



i c. Centrale = navicular =^ scajjhoideum. 



I, II, III, IV. Corresponding metatarsals. 



Plate V. THE CARPUS. 



Fig. 32. Spizella socialis. E. 18. 



Sliowing tlu'ee cavpals and three metacaipals. No iudicatlon of pha- 

 langes. 



Fig. 33. Spizella socialis. E. 19. 



The fourth carpal e now formed; phalanges also formed, and Angers, at 

 this stage widely spread. 



Fig. 34. Spizella socialis. E. 20. 



Third and fourth carpal bones united, and third and fourth metacarpals 

 unitefl at distal and pi'oximal ends. 



Fig. 35. Spizella socialis. 



Several days from the egg, and nearly capable of flight. 



