308 OSTEOLOGY OF TUBINARES AND STEGANOPODES. 



but ii lacks tbe longitudinal excavation down its postei ior aspect. Both 

 of the bones are pneumatic. Lastly, we have the smallest phalanx of 

 all belonging to the middle finger. This, as usual, is behind the broad 

 proximal joint of index, and not quite equal to half its binder border in 

 length. 



Of the pelvic limb. — In comparison with the general size of the Gan- 

 net this lower extremity is very short, though the bones composing its 

 skeleton are none the less strong in consequence. In ihefemur we find 

 the axis of the head and neck making an angle with the longitudinal 

 axis of the shaft. The head is quite distinct, globular, and excavated 

 as usual on top. Its surface is continuous with the broad articular sur- 

 face which occupies the entire summit of the bone. No t lochanterian 

 ridge rises above this latter, ami, indeed, this character of the femur is 

 but poorly developed. 



A pneumatic foramen is always seen at its most common site, on the 

 anterior aspect, just below the superior articular surface. 



The shaft is cylindrical, roughened in some places by lines and diffuse 

 tuberosities for muscular attachment, bent slightly to the front and 

 somewhat to the inner side. At its distal extremity the condyles are 

 fashioned alter the usual pattern among birds, hut all their characters 

 in Sula present sort of a lack of strong development. The fibular cleft 

 is but faintly marked, the iutei condyloid notch or fossa is shallow, and 

 the ridges in front much rounded and inconspicuous. 



Something of the same condition is extended to the proximal end of 

 tibio-tarsus of the leg, though not to such a marked degree, I think. 

 Here the enemial process rises but slightly above the articular summit 

 of tin' bone, and the pro- and ecto enemial ridges which descend below 

 it soon merge into {\\e shaft, and are, at the best, but indifferently de- 

 veloped. 



The shaft of this bone is straight and smooth and somewhat com- 

 pressed from before backward throughout. Itoffersa long ridge to the 

 fibula and is broad across where it is found. The distal extremity of 

 the bone evinces more character than the upper one. An oblique bridge 

 to confine the extensor tendons is extended across the deep groove that 

 contains them during life. 



Nearly parallel with each other, the condyles are wide apart, promi- 

 nent and convex in front, to become suppressed and low thin-crested 

 behind. 



The fibula has the usual form seen in birds, but is here particularly 

 interesting from tin' fact that it does not anehylose with the shaft of 

 the leg-bone until it arrives at the middle of its lower third, and even 

 from this low point the remainder of the bone, including an oval "ex- 

 ternal malleolus.'* stands out quite prominently. This rare condition 

 of things was pointed out also for Urinator lumme. 



Si<!<< bassana has a long oval patella, obliquely marked across its an- 

 terior surface by a groove for the tendon of the ambiens muscle. This 



