SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 1 63 



to consist in a small pitlet, with its upper and lower edges very slightly raised, but 

 in a manner hardly to suggest the idea of a "papilla" or " tubercle" as I have so 

 frequently described them for many other kinds of birds. 



The ulna develops a distinct lip of bone, that curves partly round the head of 

 the radius Avhen they are articulated in situ. This latter bone, hardly half the cali- 

 ber of the ulna, shows barely any bowing or curving at all throughout its contin- 

 uity. Distally it is deeply grooved on top for the passage of tendons, while a deep 

 circular cup for articulation with the radial tubercle on the humerus surmounts its 

 head or proximal extremity. 



The two usual ossicles, radiale and ulnare, compose the skeleton of the wrist in 

 the adult. 



The carpo-metacarpus has a total length of 6.5 cm. and is characterized princi- 

 pally by a deep pit on the palmar size of the head, between the pollex metacarpal 

 and the process for muscular attachment. This is also a very general phalacrocora- 

 cine character. The shafts of index and medius metacarpals are very straight, and 

 the latter about as long as the former, has not more than about one fourth its bulk, 

 and is compressed throughout, the flat surface of the opposed side being presented 

 to the shaft of the former. The pollex metacarpal is short, and, on the whole the 

 bone is not very unlike what we find it to be in the Cormorants. 



No perforation exists in the dorsal expansion of the proximal phalanx of the 

 index digit, and none of the terminal joints of either the thumb or the other two 

 fingers have claws at their extremities. The one belonging to the medius is com- 

 paratively long, and very sharply pointed. 



I am not familiar with the existence of any special sesamoids about the articu- 

 lations in the skeleton of the anterior extremity, at places where they exist in some 

 Auks and other water birds. 



Passing to the pelvic limb we find a femur with a length of 5.5 cm.; a tibio- 

 tarsus with a length of 9 cm.; a tarso-metatarsus of 4 cm.; an accessory metatarsus 

 of 1.4 cm., which is nearly equalled by the patella — it having a length of 1.2 cm. 

 In the foot, the skeleton of hallux measures 3.1 cm., the inside toe 4.7 cm., mid- 

 dle toe 7.5 cm., and outside toe 8 cm. — the ungual joints being included in each 

 case. 



Proportionately the femur is longer in Anhinga than it is in P. urile, and is not 

 bowed so much in the antero-posterior direction. The summit of the bone is capped 

 off with the articular surface, above which neither the caput femoiis nor the trochan- 

 terian crest, rises. The external condyle is more prominent and lower on the bone 

 than the internal one, and is deeply cleft for articulation with the head of the fibula. 



