PROFESSOR OWEN ON THE GENUS DINORNIS. 1] 
ing the head stands inwards at right angles. The head is impressed by a large pit for 
the ‘ligamentum teres.” The great trochanter rises above the level of the smooth upper 
surface continued to it from the head: there is a well-marked ridge which extends from 
the inner and back part of the shaft of the bone to the upper and back part of the inner 
condyle ; in this character it resembles the femur of the Aptery, as well as in its rela- 
tive length to the tibia. The inner condyle reaches downwards nearly as far as the 
outer condyle. The fibular fossa, outside the outer condyle, is well-marked: above it 
is a deep and rough depression. The fore part of both condyles is more prominent than 
in the femora of Dinornis. There is no pneumatic foramen: the compact wall of the 
shaft of the femur is between one and two lines in thickness. As compared with the 
femur of the Bustard, that of the Aptornis is thicker in proportion to its length, and 
longer in proportion to the tibia; and the ridge extending in the Bustard’s femur from 
the middle of the back part of the shaft towards the outer condyle, is not present in 
that of the Aptornis. 
The tarso-metatarse (Pl. III. figs. 5-8) measures three inches ten lines in length ; its 
proportions in comparison with the tibia and femur resembling those of the Apteryc. 
The ecto- and ento-condyloid cavities at the proximal end of the bone (PI. III. fig. 6) 
are deeper than in Palapteryx or Dinornis, are more equal in size, and are more widely 
separated by the intercondyloid tract and eminence: these modifications accord with 
those of the distal end of the tibia figured in vol. iii. pl. 25. fig. 6. The intercondyloid 
eminence is obtuse and relatively higher than in Dinornis or Palapteryx. ‘The calcaneal 
processes project further back and blend together in a smooth convex plate behind, 
converting the groove for the flexor tendons into a foramen which is remarkable for its 
width : its shape is shown in Pl. III. figs. 5 & 6. Figure 7 shows another character of 
the calcaneal prominence by which the Aptornis differs from the Dinornis and Palapteryz, 
viz. in the absence of the buttress-like support formed in those genera by the posteriorly 
projecting shaft of the mesometatarsal element. The back part of the shaft is even 
and almost flat, the surface being broken only by one or two narrow intermuscular or 
_ intertendinous ridges: just below the best-developed ridge near the inner side of the 
bone, is the large and well-marked surface for the attachment of the metatarsal bone of 
the hallux, 1. The anterior surface of the tarso-metatarse is convex transversely, slightly 
concave lengthwise: the distal end of the bone is so equally expanded, that both the 
inner and outer sides show a nearly equal degree of concavity. A short groove on the 
outer third of the fore part of the bone leads to the canal which pierces the confluent 
parts of the outer and middle metatarsals, two lines above the space between the two 
condyles of those bones: this canal answers to that which in the Notornis, Didus, 
Diomedea and many other birds, transmits the tendon of the adductor muscle of the 
fourth toe (Iv). The relative size and position of the condyles of the three coalesced 
metatarsals are shown in figs. 5 & 8. The middle one advances further in front of the 
others than in the Apteryr, Palapteryx and Dinornis: each condyle is impressed by a 
well-marked median groove. 
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