PROFESSOR OWEN ON THE GENUS DINORNIS. 9 



The proximal phalanx of the inner or seconH toe, ii. 1 , has the contour of the proxi- 

 mal articulation cordiform, the apex being superior, the notched base below : it is more 

 concave than in the Palapteryx robustus, and the inner and lower angle is as much pro- 

 duced as the outer one. A well-marked rough surface extends from each of these angles 

 forwards upon the under and outer surfaces of the bone. The vertical channel dividing 

 the distal trochlea is deeper than in the Palapteryx robustus, especially at its upper part : 

 the more gradual slope from the upper to the inner side of the bone, as contrasted with 

 the more vertical outer side, is better marked than in the Palapteryx robustus. The 

 inner depression at the distal end for the lateral hgament is deeper than the outer one. 

 The second phalanx is characterized by the deep lateral cavities and the prominent 

 median vertical ridge forming the proximal articulation, which is also more nearly sym- 

 metrical than in the Palapteryx robustus ; the inner division is, nevertheless, the broadest. 

 The distal articular surface extends further back upon both the upper and under sur- 

 faces of the bone. The ungual phalanx (ii. 3) shows the same unsymmetrical character, 

 produced by the more sloping inner side and the more vertical outer side, as the proximal 

 phalanx (ii. l)does: the inner side terminates below in a ridge; the outer one is rounded off 

 into the under surface: this is protuberant near the lateral vascular grooves, which are well- 

 marked. The length and slenderness of the ungual phalanx contrast better with the pro- 

 portions of the same bone in Palapteryx robustus, than do those of the preceding phalanges. 



The proximal phalanx of the middle toe (iii. 1) shows well the characters of length and 

 slenderness : its proximal articulation differs from that in the Palapteryx ingens by the 

 absence of any median vertical ridge : it is a single shallow concavity, a little deepened 

 towards the upper part : each angle between the under and lateral surfaces, at the proxi- 

 mal expanded end of the bone, supports a rough triangular prominent surface : the distal 

 trochlea repeats the same character of the deep median cleft as in the phalanx ii. 1, but 

 the divisions are more symmetrical : the articular surfaces extend further upon the 

 upper and under surfaces of the bone than in the Pal. robustus. The second phalanx 

 (hi. 2) has its proximal articulation divided and adjusted by the development of the 

 median prominence to the deeply cleft trochlea of the preceding phalanx : its distal 

 trochlea repeats the deep-cleft character. In the third phalanx (iii. 3) the distal 

 trochlea is much less deeply cleft ; and the articular surface of the ungual phalanx 

 is correspondingly simplified. This claw-bone (in. 4) repeats the long and slender pro- 

 portions of that of the second toe : the lower border of each lateral groove is notched, 

 which gives a character something hke that shown in the corresponding phalanx of the 

 Ostrich(ni. 4, PI. I.fig. 7). 



The proximal phalanx of the outer toe (iv. 1) is shorter and broader in proportion to 

 III. 1 and II. 1 than in the Palapteryx robustus: its proximal articulation is more ex- 

 tended transversely, is less notched below and less concave : the inner half has the 

 greater vertical extent, its lower angle being produced downwards : the shaft is de- 

 pressed and slopes away towards the outer side : the distal trochlea is less deeply cleft 

 than in in. 1 or ii. 1. 



VOL. IV. PART I. c 



