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PROFESSOR OWEN ON THE GENUS DINORNIS. 
of the chief leg-bone, and the need of close scrutiny and comparison of every character 
thereof in solitary fossil specimens. 
The somewhat more perfect tibia of Aptornis defossor (P|. XLI. fig. 9, and Pl. XLII. 
fig. 8) than that of Apt. otidiformis (pl. 25. fig. 5, of Trans. Zool. Soe. vol. iii.) yields 
other differences between Aptornis and Dinornis, in this bone, than are noted in the 
first Memoir (ib. p. 247). The bony canal for the tendon of the “tibialis anticus” 
and “extensor longus digitorum pedis”, is nearer the middle of the anterior surface. 
The ridge forming the inner wall of the groove thereto leading is longer and sharper, 
the bony bridge (Pl. XLL. fig. 9, f) is broader, the fibular ridge (4) is more prominent 
and more lateral. In most of these characters may be discerned a significant resem- 
blance to the tibia of Nofornis?. In the median position and breadth of the “ extensor 
tendon bridge” (jf), in the development of the inner wall of the groove, in the outer 
position and prominence of the fibular ridge, similar affinities are indicated in the tibia 
of Cnemiornis; but the exaggerated development of ectocnemial and procnemial ridges 
in that genus only comes out the stronger in the comparison with Aptornis (Pl. XLI. 
fig. 9, and Pl. XLIII. fig. 8, p,e). As in Apt. otidiformis*, the tendinal canal is less 
strictly median in Apt. defossor, and the fore part of the inner distal condyle is more 
produced and more compressed, than in Cnemiornis. 
The fibula of Aptornis defossor (Pl. XLI. figs. 10, 10 a) is 6 inches in length, has the 
usual subcompressed head, with the convex elongate articular surface for the groove of 
the outer femoral condyle; the proximal end is slightly hollowed on the inner side, in a 
minor degree conyex on the outer side; the shaft, gradually tapering as usual to a 
pointed end, which seems to have contracted a second junction with the tibia, shows 
also the two rough surfaces for tendinous attachments, but less strongly marked than 
in Cnemiornis. 
§ 6. Femur of Notornis. 
The acquisition of a second, somewhat more perfect specimen of the femur of 
Notornis, from Waingongoro, in the North Island of New Zealand, induces me to 
repeat and develope a description of the bone with special reference to the illustration 
of the Ralline affinities of Aptornis. The femur of Notornis (pl. 2. fig. 3, Trans. Zool. 
Soc. vol. iv.), in the proportions of length to thickness of shaft, in the degree of cur- 
vature, and of torsion on the axis, resembles that in smaller existing Rails and Coots 
more closely than does the femur in Aptornis or Cnemiornis. 
The head shows the same free and sharp downward production of its lower margin, 
the same proportion and position of the depression for the round ligament as in 
Aptornis, the same form and degree of extension of the articular surface upon the neck, 
the same transverse convexity of that surface. ‘The great trochanter rises higher than 
this surface, but is relatively less elevated than in Aptornis; it is relatively as broad ; 
1 Trans. Zool. Soc. yol. ii. pl. 35, 8,9. 2 Tb. vol. iv. p. 12, pl. 2. fig. 4. 3 Tb. vol. v. p. 402. 
