l8 Shufklut, Osteology of OrthorJumiphus magnirostris. [^^^ '"^'^1^. 



hemielliptical, with the free margm finished off with a thickened 

 edge. (Length, 22 mm. ; height, 7 mm.) In outhne and other 

 particulars this " radial crest " agrees with that part of the 

 humerus in Chionarchus minor and Hcematopus niger ; while in 

 Squatarola and Belonopteriis it is relatively shorter and rather 

 more pointed at the centre of its free margin, and decidedly more 

 so in most Laridce. In Arenaria interpres it is also pointed, with 

 the point slightly bent palmad. 



The " incisura capitis " is deep, and has a length equalling that 

 of the head of the bone. To its ulnar side is to be noted the deep 

 excavation, entirely surrounded proximally by a raised margin, 

 known as the " pneumatic fossa," but here harbouring no foramina 

 for that purpose. At its summit, proximad, there is a pro- 

 minently developed tubercle — the tuberculum internum. On the 

 palmar aspect of the head of this humerus the " incisura capitis " 

 is deep and long, and the area immediately beyond it — the roof 

 of the pneumatic fossa, as it were — is smooth and convex. As 

 already stated, the subcylindrical shaft is but shghtly curved, 

 and, beyond its smoothness, lacking in any particular character. 



At the distal extremity neither the enti- or the ecti-condylar 

 process is especially prominent (fig. 13) ; while the latter in such 

 birds as Chionarchus minor, many LimicolcB and Longipennes, is 

 a very conspicuous character of the humerus. 



The excavation for the insertion of the brachialis anticus 

 muscle is rather deep, and the articular tubercles beyond it are 

 prominently developed. 



Upon comparing, character for character, as presented on the 

 part of all the humeri at hand at this writing, I find that the 

 humerus of Orthorhamphus magnirostris is much more like the 

 humerus in Hcematopus niger than it is like that bone in any other 

 species ; and when I say this, it must be remembered that I have 

 not a humerus before me from a specimen of (Edicnemus. Indeed, 

 the skeleton of the hmbs in the case of that genus lacks the 

 femora, the humeri, the proximal ends of the tibio-tarsi and 

 radii, and of one ulna. 



Neither the radius nor the ulna in Orthorhamphus magnirostris 

 present any peculiar characters. Either bone has the usual 

 curvature of its shaft at the proximal third, so that, in the 

 articulated hmb, we find there a much larger " interosseous 

 space " than exists between these bones for the remaining two- 

 thirds, distad. Their shafts are smooth, and more or less 

 cyhndrical in form at the middle sections of their continuities. 

 Ulna almost entirely lacks the papilliform elevations down its 

 shaft for the quill-butts of the secondary feathers, which are more 

 or less prominent in most Laridce, some Charadriidce, and the 

 Oyster-catchers. 



Possessing the usual ornithic characters, as they pertain to 

 birds of the higher groups, the radiate and ulnare ossicles of the 

 carpus are both present, well developed, and make the usual 

 articulations with the bones of the antibrachium and manus. 



