° i9l4 ] Shufeldt, Osteology of the Passenger Pigeon. 361 



Broad and somewhat shallow, the pelvis of the Passenger Pigeon 

 is, nevertheless, capacious, and reminds one of this bone in some of 

 the TetraonidcB. Its sacral roof is a broad, lozenge-shaped one, in 

 close contact with the ilium upon either side; but coossification 

 does not take place at any point along the sutural line. 



As we might expect in a bird of such powerful flight, the keel or 

 carina of the sternum is very extensive, with its fore-part thick and 

 strong. There is a pair of xiphoidal processes on either side, 

 posteriorly, each having an expanded distal end as shown in Figure 

 1 of the Plate. Four costal ribs articulate with either costal 

 border, and a minute manubrium is seen to project in front. 



Powerful flight in this bird also accounts for the presence in its 

 skeleton of a scapular arch, with its usual component bones large 

 and strong. Os furculum is of a broad, U-shaped form with a 

 minute hypocleidium below. Either scapula is enlarged posteriorly, 

 the distal extremity being truncate from within, outwards. A 

 coracoid is an unusually large, long bone for a bird of the size of this 

 pigeon, and it is very strong and straight. The os furculum does 

 not meet the scapula, on either side, in articulation, and the free 

 ends of this arch are but slightly expanded. 



The Limbs: — As we would naturally expect, the skeleton of the 

 pectoral limb indicates great power of flight. The several bones, 

 though short, are massive, and in close and extensive contact at 

 their articulations. 



The humerus is short and straight and the shaft correspondingly 

 stout. Its radial crest is triangular in outline as shown in Fig. 5. 



Radius of the antibrachium is also straight, while the massive 

 ulna exhibits more or less curvature along its entire continuity 

 (Fig. 4). 



In extreme length the humerus measures 4.3 cms.; the ulna 7.55 

 cms., and the radius, as in the case of the humerus, 4.3 cms. All of 

 these bones, which is also the case in the pelvic limb, do not quite 

 come up to these measurements, owing to there having been a 

 slight obliquity in the point of view as they were placed to be 

 photographed. This could not be avoided, as the bones of the 

 limbs are articulated, and I had no right to separate them. The 

 carpo-metacarpus has an extreme length of 2.9 cms., as in the Plate. 

 Comparatively speaking, the bones in the thigh, leg and tarsus are 



