SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 211 



neither notches or indentations. Ventrally, the carina extends the entire length of 

 the bone, its lower margin being very convex and thickened ; the lateral edges of the 

 latter extending beyond the sides. The anterior carinal boundary is sharp and short 

 surmounted above by a rudimentary manubrium. Either costal groove is deep and 

 wide, and the coracoids, when articulated in situ, meet in the median line above, where 

 they separate the anterior sternal border and the small trihedral manubrial process. 



The OS furcula is of the U-shaped pattern, and is coossified, as has been said, with 

 the sternum and coracoid. Its rami are narrow and compressed, with its hj^poclei- 

 dial portion below very broad, triangular in outline, slightly concaved in front, 

 and withal antero-posteriorly compressed. Above, the clavicular ends are trans- 

 versely very thin. Either one shows tw^o places of bony fusion ; one at the tip, and 

 a still more extensive one in front of the head of the coracoid. Mesiad, between 

 these, there exists an oval foramen. The clavicular extremities are separated from 

 each other by a distance of 6 centimeters. By far the largest bone of the pectoral 

 girdle is the coracoid. Either one of them has a height of 8.5 cm. with a large 

 shaft and broad sternal end. A minute epicoracoidal process is present, and the 

 clavicular process, although pretty well developed and curving forwards, does not 

 reach the end of the clavicle by quite an interval. The glenoid cavity faces more 

 than usual to the rear, much as it does in an Albatross. Measuring on its chord, a 

 scapula has a length of about 8 centimeters. Its inner border is convex, and its 

 outer more decidedly concave. For its middle third, the bone is narrow and thick- 

 ened, the distal extremity being slightly dilated, compressed from above down- 

 wards, and brought to a rounded point posteriorly. Its coracoidal extremity is 

 also much compressed in the vertical direction, very wide from side to side, with its 

 inner angle drawn out into a well-developed process, and with a small glenoidal 

 facet occupying the other one. 



The Pectoral Limb. — The bones making up the skeleton of the upper extremity 

 are all completely pneumatic, and, as compared with those of the pelvic limb, are 

 chiefly remarkable for their enormous comparative lengths. This is well shown in 

 the following table : 



Length of Humerus 21.0 cm. 



" Femur 5.7 " 



Ulna 27.5 " 



" Tibio-tarsus 7.5 " 



" Eadius 26.6 " 



Fibula 6.5 " 



" Carpo-metacarpus 13.0 " 



" Tarso-metatarsus 2.4 " 



" Index digit 12.5 " 



" Mid-anterior toe 7.6 " 



