302 NEW YORK STATE MUSEUM 



little joint behind it extending rather more than half way down 

 its posterior border. 



I have yet to find a true American anserine bird that possesses 

 a pneumatic bone in its pelvic limb. All the species before me 

 entirely lack this character. 



In Spatula the trochanterian ridge of the femur has a thick, curl- 

 ing crest on the anterosuperior aspect of the bone, but at the summit 

 it is leveled down to the same plane with the articular surface. The 

 head is rather large and sessile and the excavation for the round 

 ligament shallow. 



We find the distal extremity unusually large ; indeed, all the 

 bony structures that enter into a duck's kneejoint are large and 

 massive. This is particularly the case with the condylar extremity 

 of the femur in Clangula, where these prominences are power- 

 fully produced behind, and a wide and deep cleft splits the outer 

 one for the fibular head. In this form, too, a deep pit is found in 

 the popliteal fossa. 



Returning to the femur of Spatula, we note that its shaft is 

 nearly straight, being marked by the usual muscular lines, while 

 the pit just spoken of is absent. The rotular channel extends 

 slightly up the shaft above the condyles, whereas in Clangula 

 this is not the case, and in this duck the femoral head is notably 

 large and extensively excavated on top ; the lower third of its shaft 

 is somewhat bowed to the front and a little twisted, recalling to 

 one's mind the power of that peculiar arch as exhibited in such a 

 marked degree in Gavia. 



The Spoonbill, and I suppose other ducks will show the same, 

 has an extraordinary formed patella, being flat on top, wedge-shaped 

 in front, broad and concave behind, deeply excavated and arched 

 below, while across its anterior face it is profoundly slit in the 

 oblique direction for the tendon of the ambiens muscle. 



In the tibiotarsus we find a large, flakelike, and jutting procnemial 

 crest, which curls toward the fibular side and ends abruptly high 

 up on the shaft. The ectocnemial crest is also turned outward, but 

 is low and thick. These prominences are but slightly elevated 

 above the articular .summit of the bone, while in Clangula they 

 are carried up in such a manner as almost to rival the grebe in this 

 particular, having very much the same form. 



The tibiotarsal shaft in Spatula is straight, smooth, and sub- 

 cylindrical. It afifords at its outer side the usual ridge for the 

 accommodation of the fibula. This is very long in the garrot. 



