242 



OSTEOLOGY OF ANSERES. 



Id all tin' Anatidco that 1 have examined a pro-pubis is to be found 

 jutting forward from its usual site. This is the case in Spatula. Be- 

 hind this a .small obturator foramen, nearly closed in, is to be noted, 

 while the obturator space is very large and completely surrounded by 

 bone behind, through the foot-like process afforded by the ischium. 

 This latter projection articulates with a facet, intended for that purpose, 

 on the upper border of the post pubis. 



The post-pubis is a slender rod as it passes beneath the obturator 

 space, but after its articulation with the ischium posteriorly it has its 

 width nearly doubled, and in Glaucionetta the hinder ends are slightly 

 enlarged. This latter Duck departs from the above description princi- 

 pally iu such a minor detail as having a relatively much larger ischiae 

 foramen and longer obturator space. 



In all of these species we find the pelvic basin upon the ventral aspect 

 very capacious, both as to its depth and width. 



As 1 have already stated elsewhere, the pelvis in Olor has a very dif- 

 ferent form from that boue as we find it in the Ducks. It assumes a 

 shape that at once brings to our mind the mergiue pattern, with its 

 greater length as compared with its width; the almost entire disappear- 



FlG. 23. Left lateral aspect of pelvis of Spatula clypcata ,■ life size. Same specimen as Fig 



22. 



a nee of the interdiapophysial foramina, and the broad, paddle shaped 

 extremities of the post-pubic elements. This model sees its extreme 

 modification in the Pygojwdcs ; and if we remove the intrasternal 

 chamber for the accommodation of the tracheal loop, we find in the 

 sternum, too, of the Swan a great deal to remind us of that bone in 

 Urinator. 



>Si><<hiI« possesses, in common with most Ducks, a completely non- 

 pneumatic shoulder girdle. In it we find abroad, U-shaped furcula, de- 

 void of hypoeleidium and with its long, pointed, clavicular heads extend- 

 ing almost directly backward. On the upper side, where either of these 

 latter merge with the limbs, we find a peculiar little peg-like process, 

 that is quite characteristic of most Anatidce. The scapula is long a"d 

 curved, the curve being in the plane of its blade, with the convex bor- 

 der mesiad. Its posterior end is simply rounded off, and its head makes 

 a firm articulation with the broad, scapular process of the eoracoid, 



