ShUKKI.DT : OSTKOI-OCV OK THK H KKODIONK.S. 205 



Other birds, but when compared with the size of its own tibia (Figs. 

 19 and 20). 



The upper surface of its distal end is devoted entirely to the facet 

 for articulation with the condyle of the femur. IJelow this the bone 

 is compressed from side to side, and produced from before, backwards. 

 Then rapidly contracting it presents a roughened surface intended for 

 ligamentous attachment to the fibular ridge of the tibia. Near this we 

 see the tubercle for the insertion of the tendon of the biceps. The 

 remaining length of the fibula becomes almost needle-like in its dimen- 

 sions, and makes no osseous connection with the tibia whatever, pass- 

 ing but little below the upper third of its shaft, which when the bone 

 is removed shows no evidence of its contact, more than the roughness 

 of the fibular ridge. 



Aniea candiiUssima has a fibula that agrees in all respects with the 

 one I have described for the Great 151ue Heron. In Nycticorax it differs 

 in one important particular, and this is, that after passing its articula- 

 tion with the fibular ridge of the tibia, its almost thread-like dimen- 

 sions are carried well below the middle of the shaft of the leg-bone to 

 unite with it by ossification, for at least a third part of its length. 



Next in order we have to notice the tarso-mekitarsiis. The differ- 

 ences that this segment of the lower extremity exhibits among the 

 various herons, seem to be scarcely worth the mention. So I expect 

 a description of the bone as it is found in Ardea herodias, will answer 

 with sufficient exactness for the group. 



Different views of the tarso-metatarsus are shown in figures 15, 16, 

 17, and 18 all drawn from an adult specimen of the Great Blue Heron. 



A very prominent tubercle occupies the anterior part of the proxi- 

 mal extremity. It stands between the two elliptical concavities in- 

 tended, when articulated, for the condyles of the tibia. The 

 margins surrounding the extremity are raised at the sides and sharp- 

 ened. Posteriorly, we can also see from this view, the three processes 

 composing the hypotarsus . Of these the innermost one projects the 

 farthest backwards, as well as extending the greatest distance down the 

 shaft. The outermost one of the three is the smallest, being just about 

 half the size of the innermost one. The middle one falls between 

 these two so far as its height is concerned, but it is as long as the 

 innermost one (Figs. 17 and 18). 



In order to support this great tendon-grooved hypotarsus, and broad 

 articular surface, the shaft of the bone at this end is proportionately 



