SHUPELDT : OSTEOLOGY OF THE STEGANOPODES 201 



the caput femoris is but little excavated. Distally, the condyles appear to be 

 somewhat antero-posteriorly compressed, and transversely spread apart from each 

 other. The external condyle is slightly the lower and larger of the two, and 

 it is deeply cleft behind for the head of the fibula. Anteriorly, the rotular chan- 

 nel is shallow, nor is the popliteal fossa on the other side of the bone as deep in 

 proportion as we find it in many other birds, both large and small, (PL XXVII., 

 Fig. 32). 



A tihio-tarsus instead of being bowed in the antero-posterior direction as it often 

 is, it curves the other way so that the fibular border of the bone is con vexed, and 

 the opposite one, correspondingly, or even rather more, concaved. The extremities 

 are large, but the several cnemial processes at the proximal one are but very moder- 

 ately developed. Low and long, the fibular ridge extends down half the length of 

 the shaft, and its articular margin or border is roughened. The tibio-tarsus of P. 

 shaiyei exhibits these characters very well, as they are seen in the Pelecanidse 

 generally (PI. XXVIL, Fig. 33). 



• At the distal end of the tibio-tarsus, the large condyles of the usual reniform out- 

 line, protrude prominently to the front, while behind they almost immediately 

 merge into the general surface of the lower end of the shaft. The intercondylar 

 interval is deeply excavated between them in front ; at;their lateral aspects the points 

 for tendinal and ligamentous insertion are roughened and distinctly defined. A 

 small bony bridge, such a frequent ornithic character, spans obliquely the anterior, 

 longitudinal channel for the passage of tendons. In the deepest part of this recess, 

 and directly under this little osseous bridge, a large pneumatic foramen enters the 

 shaft of the bone. It is the principal aperture of this kind, by far, in the bone, and 

 exists in the same place in the shaft of the fellow of the opposite side. 



A fibula has its head and articular surface thereon moderately well developed, 

 but the bone contracts rapidly as we proceed in the direction of its distal end, and 

 after passing the articular surface for the tibia, it comes to be little more than a 

 stout, bony thread, that by no means reaches the condyle of the tibio-tarsus, nor 

 does it anchylose with its distal end. 



Pelicans have, comparatively speaking, a very small patella, which is roughly 

 wedge-shaped in form, with the flat base below, and the superior edge rounded, and 

 not especially sharp. 



The tarso-metatarsus is a stout, straight bone, with pronounced characteristics. The 

 intercondyloid process upon its summit is rounded and conspicuous. Immediately 

 below it, in front, terminates the usual longitudinal channel found on the anterior 

 aspect of the shaft. It is deep here and opens into the shaft by a double pneu- 



