SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 161 



here. They give rise to long, lateral xiphoidal processes, and a shorter mid-xiphoidal 

 process. On its thoracic aspect the sternal body as a whole is well concaved — uni- 

 formly so, as the position of the heel beneath is but barely indicated down the 

 median line. The form and proportions of the sternum in Anhinga are well shown 

 in my figures 5 and 6. 



The OS furcula is of the typical U-shaped pattern, with large, expanded clavicular 

 heads. There is but the barest rudiment of a hypocleidium below, while a facet is 

 present on the nether side of it, for articulation with the carinal angle of the keel of 

 the sternum. Either broad, laterally-compressed clavicular head, is bent rather 

 abruptly downwards; a projecting, facet-bearing shoulder is developed for the coracoi- 

 dal articulation. Above either of these facets we note a strong process pointing back- 

 wards, which, when the os furcula is articulated in situ, rests upon the summit of 

 the corresponding coracoid. (See Figs. 7 and 8.) 



Both Darters and Cormorants have unusually long coracoids. In Anhinga the 

 coracoid is longer than the femur. Its sternal end is considerably expanded, and 

 shows a wide and rather deep excavation on its posterior aspect for the coracoidal 

 groove and facet upon the sternum, while anteriorly the corresponding surface is 

 narrow and shallow. A costal process is not developed, but that border is convexly 

 rounded and sharp. The shaft of this bone is antero-posteriorly much compressed, 

 and in front a strong, muscular line marks it longitudinally, especially near the 

 sternal end. The scapular process is much aborted, but the head is quite massive and 

 tuberous. Its entire antero-mesial aspect is occupied by an oval facet for articula- 

 tion with the clavicular head of the furcula. The scapular facet is small, but the 

 glenoid surface is of fair size. 



Quite uniform in width and moderately pointed distally, the thickish blade of a 

 scapula has its posterior extremity but very slightly bent outwards. The anterior 

 end of this bone is wide transversely, and the long acromial process decidedly 

 tilted up. The glenoidal process also stands out rather prominently, while the 

 articular facet for the coracoid is comparatively small. Just posterior and beyond 

 the glenoidal facet, the border of the scapula is broadly rounded, but is sharp all 

 along its mesial edge, clear to the tip of the acromial process. It is only the distal 

 third of the bone that is vertically compressed and at all blade-like. 



On the Appendicular Skeleton. 



Being thoroughly non-pneumatic, the long bones of the limbs in Anhinga are 

 solid and heavy. Although not so very far from being double the size, the humerus 

 of Fregata w^eighs about the same as the humerus of the species of Darter we are now 



