178 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Though both tlie exterior proportions and the color of the Coscoroha 

 are much Uke those of the Swans, there are, however, considerable dif- 

 ferences. 



In the first place, the bill is not of equal breadth for the whole length 

 as in the Swans, but broadens, comparatively, considerably towards the 

 tip, being, besides, more depressed in front of the nostrils, so that, on 

 the whole, it is a perfect duck-bill. Add to this that the lores, at all 

 ages, are comijletely feathered. The relation of the wing-feathers is 

 nearly identical, but there is, however, a ditfereuce, the inner web of the 

 third primary of Coscoroha not being sijiuated, as is the case in all species 

 of Cygninw. The relatively inucli longer hind toe of Coscoroha is another 

 not unimi)ortant difference, the whole nail touching the ground when 

 the bird walks. 



The interior differences are even more essential. 



As I have just above given a short characteristic of the most inter- 

 esting and peculiar facts in the osteology of the SwaTis, I here only in- 

 tend to enumerate the more essential osteological features wherein Cos- 

 coroha differs from the Cygnina', mostly leaving to the reader himself to 

 draw the comparison. 



The sl:ull shows only few differences besides the above-mentioned pe- 

 culiar sliape of the bill. The os lacrymale, however, is more duck-like 

 than in the Swans, the fore processes Deing more elongated. On the oc- 



Pelvis of Coscoroha Candida.— I'fo. 11816, TJ. S. Nat. Mus. 



ciput the two fontanelles, above the foramen magnum, are to be found as 

 well circumscribed, long, and rather narrow apertures (4 by 1.5'""'). The 

 vertehrw colli amount to 21, the last supporting a free rib without epi- 

 pleural appendage. Seven vertehrw of the dorsal section with their pleura- 

 p)ophyses and hwmopojjJiyses, the five first having uncinate processes. One 

 sacral rib. The number of free coccygeal vertehrw is only five plus the 

 pygostyle. The sternum is quite duck-like in its outlines, the lateral mar- 

 gins converging to the articulations of the last dorsal hmmapophyses, and 

 from this jKjint again diverging. The costal horder is comparatively 

 short. The notches of the hind margin very deep, making about ^ of 

 the whole length of the sternum. The pectoral ridge for the origin of 

 muse, pectoralis secundus runs backwards to the end of the crista, the 

 lower border of which forms an undulating line, being higher ou the 



