210 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 20, 



the rest of the trochlear surface is a little concave transversely, with 

 a feeble median rising behind. The bridge is to the left of the mid- 

 line, short, and transverse : the lower outlet is above the inner 

 side of the intercondyloid space : its lower border bounds above the 

 shallow cavity at the upper part of, and continuous with, that space. 

 There is a short ridge on the outer side of the bridge : the ecto- and 

 ento-condyloid surfaces are as in Grus. 



The distal end of the tibia of the Woodcock {Scolopaoc rusticola) 

 closely conforms to that of the Oyster-catcher. The trochlea is a 

 Uttle flatter below, and the inner condyle is relatively smaller and 

 more prominent : the lower border of the bridged canal, and a ridge 

 continued outwards from it, define the shallow intercondyloid cavity 

 above. 



In the Gallinule {Gallimda chloropus, fig. 9) the bridge is broad, 

 transverse and submedian : the lower outlet is large, and opens 

 above the intercondyloid space, in which no particular cavity is 

 defined. The canal leading to the bridge is broad, deep, and bounded 

 by a ridge on each side. The inner condyle is much narrower than 

 the outer one : the trochlear space is not flattened below ; it is 

 narrow and concave behind. 



In the Notornis, or large short-winged Coot of New Zealand, 

 figs. 10«, 10 5, the breadth rather exceeds the depth of the con- 

 dyles : the intercondyloid space is more than twice the breadth of 

 either condyle. The bridge is of moderate breadth, transverse and 

 median in position : its lower outlet is a transverse ellipse, looking 

 forwards, just above the wide and shallow intercondyloid space : the 

 canal leading to the bridge is wide and deep, with a boundary ridge 

 on each side : the under and back parts of the trochlear surface are 

 broader and flatter than in the Gallinule. The narrow inner con- 

 dyle is very prominent. 



The Aptornis (figs. 1 1 «, 1 1 5) chiefly differs from the Notornis 

 in the less median position of the bridge, and the less depressed sur- 

 face external to it i also in the much shallower canal leading to it, 

 which has no external boundary ridge ; the intercondyloid space, 

 though wide and shallow, is less so relatively than in the Notornis : 

 in other respects the tibiae of this and the foregoing New Zealand 

 birds resemble each other at the lower end. 



Order Cursores. 



In the Apteryx (fig. 12) the breadth and depth of the condyles 

 are equal : the inner one is the more prominent ; the intercondyloid 

 space is rather narro>ver than either condyle. The bridge — some- 

 times unossified — is internal ; external to it the surface of the bone 

 is moderately convex, and divided by a transverse linear groove from 

 the intercondyloid space, in which is no special depression. The 

 hinder trochlear space is slightly concave transversely. 



In Binornis (figs. 2 a, 2 b) the breadth and depth of the condyles 

 are equal : the outer condyle (b) is the broader, the inner one (a) is 

 the more prominent ; their articular surfaces are so continuous as to 



