156 ODONTORNITIIES. 



Measurements of Metacarpal. (Ichthyornis victor, No. 1724.) 



Length of right metacarpal, 39.5" 



Greatest diameter of proximal end, 11.2 



Transverse diameter of proximal end, 4.7 



Transverse diameter of shaft of second metacarpal element, 4. 



Transverse diameter of shaft of third metacarpal element 1.7 



Greatest diameter of distal end, 7.6 



Transverse diameter of larger articulation, 5.5 



Length of first metacarpal element, 7. 



Measurements of Metacarpal. {Ichthyornis anceps, No. 1208.) 



Greatest diameter of distal end, ' 6.75™ 



Least diameter of distal end, 3.5 



Transverse diameter of outer articular face, 5. 



Vertical diameter of outer articular face, 2.25 



Measurements of Metacarpal. (Ichthyornis agilis, No. 1209.) 



Vertical diameter of proximal articulation, 6. m 



Transverse diameter of proximal articulation, 5. 



Transverse diameter of shaft, 3.8 



Measurements of Metacarpal. (Apatomis celer, No. 1734.) 



Length of right metacarpal, 36. m 



Greatest diameter of proximal end, 8.5 



Transverse diameter of proximal end, 4. 



Diameter of shaft of second metacarpal element, 2.8 



Diameter of shaft of third metacarpal element, 1. 



Greatest diameter of distal end, 4.5 



Transverse diameter of distal end, 3.2 



The Wing Phalanges. (Plate XXXI, figures 5-8 and 16-19.) 

 The first phalanx of the median or second digit of the wing (number 

 1726) is in Ichthyornis a robust bone, but tapers rapidly in its shaft from 

 the proximal toward the distal end. On the ulnar side, it is, however, 

 considerably expanded, and the thin extension is in most of the specimens 

 thoroughly ossified, and supported on its anconal surface by two oblique 

 ridges. Of these ridges, the first arises near the proximal end of the bone, 

 and is only faintly indicated, or is partly confluent with the oblique margin 

 of the expansion. It ends in a prominent thickening- at the margin of 

 the bone. The second ridge arises near the middle of the bone, and passes 



