OSTEOLOGY OF THE DODO. 79 
dyle is more produced and sharper in Aptornis, the fore part of the same condyle is 
less produced. 
The femur in Cnemiornis' and Dinornis? is much thicker, in proportion to its length, 
than in either Aptornis or Didus. In Pezophaps the great trochanterian ridge rises 
higher above the neck, and the shaft has a more uniform thickness, with the inner 
contour less concave, than in Didus. 
The characters which have been noted at the proximal and distal ends of the tibia of 
Didus are repeated in those of the tibia of the Goura. ‘The difference in size is more 
marked than in the femur; the length of the tibia of Gowra coronata is 4 inches 7 lines, 
and its shaft is more slender, in proportion to its length (Pl. XXIV. fig. 13), than in 
Didus (Pl. XXII.). The tendency to a trihedral form of the shaft is less marked in 
Goura; the anterior prominences of the distal condyles are thicker in proportion to the 
intervening fossa. 
In the Vulture the fibular ridge is more parallel with the long axis of the shaft than 
in Didus; the tendinal canal is less cylindrical, has an oblique course from the middle 
of the anterior surface towards the inner condyle; the fore parts of both distal condyles 
are less produced and less convex; the distal end is narrower from before backwards in 
proportion to its breadth ; both extremities of the bone are less expanded in proportion 
to the shaft than in the Dodo. 
In the great Plover (Hdicnemus crepitans) the tibia, as in other Gralli, is longer in 
proportion to its thickness than in Didus; the epicnemial process rises higher above and 
projects further in front of the condylar surfaces before it divides into the pro- and 
ectocnemial plates; and these are relatively more produced. ‘The fibular ridge is 
shorter in proportion to the length of the tibia, is more prominent, and more parallel 
with the axis of the shaft. The distal condyles project further backward than in Didus. 
The tibia in Charadrius, Otis, Tantalus, Grus, Ciconia, Mycteria, Porphyrio, opposes 
similar or equivalent differences to those in @dicnemus, against the affinity of Didus to 
any of those Gralle. 
In the comparison of the tibia of this extinct flightless bird with that of the Cnemiornis, 
the wonderful development of the plates and processes at the proximal end of the bones 
in the New Zealand bird is strikingly manifested. In Cnemiornis the fibular ridge runs 
in a line with the shaft, and does not incline from above obliquely forward as in Didus 
and the Doves; the ridge on the outer side of the distal fourth of the bone is stronger 
and sharper in Cnemiornis; the tendinal canal is transversely elliptical, medial in 
position, with a slight inward inclination; the intercondyloid fossa is much wider in 
Cnemiornis. The differences, indeed, in all the characters of the tibia, as compared with 
Didus, in the Vultures, Plovers, Penguins, and terrestrial flightless birds tend to render 
more instructive and convincing the resemblances which Pigeons present in the same 
characters to the extinct Mauritian bird. 
' Trans. Zool. Soe. vol. y. pl. 65. fig. 1. ? Thid. fig. 5, 
