154 ME. E. T. NEWTON ON THE EEMAINS OE A 



one notices a similar curvature of the inner side and projection of the inner condyle 

 beyond the contour of the shaft (fig. 5) ; also the rounded inner side of the shaft and its 

 sharp outer or fibular margin ; the greater antero-posterior extent of the inner condyle 

 as compared with the outer ; the form of the trochlear surface ; the position of the 

 groove for the peroneus tendon ; and the manner in which the ridge, rising from the 

 inner side of the bridge, may be traced upwards to the procnemial crest. In all these 

 points the two tibio-tarsi are remarkably alike. The fibular crest is a little more 

 prominent in the Goose than in the Croydon specimen ; but the latter has this crest 

 more projecting than could have been inferred from the Meudon example. Notwith- 

 standing these resemblances, there are some very decided points of difference. In the 

 Goose the supratendinal bridge and the canal which passes under it are in the middle 

 line of the bone, while in the Croydon species both are placed towards the inner side. 

 The Meudon species is nearer to the Goose, inasmuch as its bridge is almost in the 

 middle. The Goose has the lower aperture of the bridge looking directly forwards, 

 and as nearly as possible in the middle. The lower margin of the aperture is formed 

 by a transverse ridge of bone, and is rather more prominent than the upper margin. 

 In the Croydon fossil the lower aperture of the bridge looks obliquely downwards 

 and inwards, and is considerably nearer to the inner than to the outer side; and 

 the lower margin of the aperture is not so prominent as the upper. The bridge 

 itself, in the Goose, is in a depression, while in these fossils it stands prominently 

 forward. The deep intercondylar depression seen in the fossil is only slightly indi- 

 cated in the Goose (PI. XXVIII. fig. 5) ; in the Swan this depression is perhaps a 

 little deeper. 



The New-Holland Goose (Cereopsis novas-hollandiw) makes a nearer approach to 

 Gastornis, for while its tibio-tarsus agrees with the Common Goose in all those points 

 in which the latter agrees with Gastornis, it has, in addition, both the tendinal canal 

 and the aperture of the bridge placed towards the inner side. Cereopsis has also a 

 more definite intercondylar depression ; but still this depression is nothing like so deep 

 as in Gastornis. 



The Herring-Gull (Larus argentatus, PI. XXVIII. fig. 6) has the lower end of its 

 tibio-tarsus in some respects nearer to Gastornis than Cereopsis ; but in other particulars 

 it differs more widely. In this Gull the tendinal canal is well towards the inner side, 

 and the lower aperture of the bridge is also towards the inner side, and looks downwards 

 and inwards. At the same time the lower margin of this aperture is less prominent 

 than in the Goose, and there is a shallow intercondylar depression, thus making an 

 approach towards the deep depression of Gastornis ; indeed, the same ridge and depres- 

 sion may be seen in both, although the ridge just below the bridge-aperture is stronger 

 in the Gull. The roughened prominence seen in Gastornis at the outer side of the 

 lower aperture of the bridge (PI. XXIX. fig. 7, La) is present also in the Gull. The 

 chief differences between the Gull's tibio-tarsus and that of Gastornis ; are the more 



