[parks] new species OF TRACHODONT DINOSAUR 59 



Phalanx IV^ is normal, but of very irregular shape and with 

 a proximal articular surface very much smaller than the apposed 

 distal articular surface of IV\ 



The unguals of digits II and III are distinct hoofs, the ungual of 

 digit II being longer and more pointed than that of digit III. Both 

 bones show a lack of symmetry in accord with their inflected position. 

 The ungual of digit II of the right foot has not yet been recovered, 

 but that of digit III is exactly the same as the corresponding bone in 

 the left foot, showing that the lack of symmetry is not due to dis- 

 tortion. 



The first three phalanges of digit V are free, normal, transversely 

 elliptical bones of gradually decreasing size. The last phalanx is a 

 small, symmetrically ovoid bone 12 mm. long. 



It is commonly thought that the loss of two hoofs in the manus 

 is evidence that the race was in process of giving up the use of the fore 

 limb for progression. If this is true, the present animal had advanced 

 further in this respect than other members of the family. The in- 

 flection of the two hoofs and the development of the fourth phalanyx 

 in the fifth digit point in this direction. On the other hand, the speci- 

 men was found fairly low in the Belly River beds and is evidently older 

 than the trachodonts of the upper part of the Belly River and of the 

 Edmonton formation in which this remarkable phalangeal arrangement 

 is not shown. 



