202 Annals of the Carnegie Museum. 



The condyles of this bone are strong and massive. The articular 

 surface of the inner one is broad behind, and so far produced in this 

 locality as to render the popliteal depression appear more than usu- 

 ally concave and excavated. Above each condyle behind is seen a 

 well-marked tubercle, with pits on their outer sides for the insertion 

 of lateral ligaments and muscles. The external condyle has the usual 

 fibular groove, deeply cleft and carried down behind well nigh to its 

 base ; it is more prominent than its fellow, though not as broad. Be- 

 tween them, the inter-condyloid fossa is moderately deep, rather wide, 

 and carried up on the anterior aspect of the shaft as a " rotular chan- 

 nel" of like dimensions, though not mounting as high as it does in 

 some birds. Of these two condyles, the external one is rather the 

 lower, the bone being held in the vertical position. 



I fail to find 2. patella present in any of the ArdciiKP. ; in Nycticorax 

 a thickening in the ligament lakes place at the usual site of this sesa- 

 moid in other long-legged birds where it is found, but this liga- 

 mentous enlargement is entirely devoid of any osseous deposit. 



The tibia of Anlca herodias as we might expect is a very long bone, 

 and in every particular typical as found in Herons generally. Viewed 

 directly from above, on its proximal end (Fig. 21) we observe that it 



Fi<;. 31. Left lateral view of the sitrnnmoi Aritea ((mi/idissi/i/n. Adult specimen. 

 Natural size, by the autlior. 



has a roughly quadrilateral outline, its general surface sloping towards 

 the fibular side. 



The intercondyloid tubercle is prominent, and situated rather ex- 

 ternal to the center of this surface, while anteriorly it is bounded by 

 a low cnemial crest. 



Regarding the shaft from in front (Fig. 23), we notice that the 

 pro- and ectocnemial ridges are but moderately developed, and very 



