LARIDiE.] 



OSTEOLOGIA AVIUM. [STERNIN2E. 



Numbering of the Vertebrce and Ribs in Natatores. 





Cervical. 



Dorsal. 



Sacral. 



Caudal. 



True ribs. 



False ribs. 



Plectropterus Gambensis . 



15 



7 



16 



6 



7 



2 



Cereopsis Novas Hollandiae 



17 



8 



17 



6 



5 



1 



Bernicla Brenta 



17 



7 



18 



6 



9 



2 



Anser cygnoides , 





17 



6 



19 



6 



9 



2 



Cygnus coscoroba 





20 



7 



19 



8 



9 



2 



atratus 





21 



8 



19 



8 



9 



2 



ferus . 





23 



6 



21 



7 



8 



2 



Tadorna vulpanser 





16 



6 



15 



7 



8 



2 



Casarka rutila . 





16 



6 



17 



7 



7 



2 



Dafilla caudacuta 





16 



7 



16 



6 



8 



2 



Anas boscbas . 





15 



6 



16 



6 



7 



2 



Dendrocygna arcuata 



15 



6 



18 



6 



7 



2 



Chaulelasmus strepera 



14 



7 



16 



6 



7 



2 



Oidemia nigra . 



14 



6 



16 



6 



8 





Fuligula marilla 



15 



6 



16 



6 



8 





Clangula Glaucion . 



15 



6 



16 



6 



8 





Erismatura Leucocephala . 



13 



6 



13 



7 



6 



2 



Biziura lobata . 



14 



6 



15 



6 



9 





Mergus albellus 



15 



6 



15 



6 



7 



2 



Colymbus septentrionalis . 



11 



7 



16 



6 



8 





Podiceps minor 



16 



5 



13 



6 



6 





Podiceps cristatus 



19 



7 



17 



6 



7 





Alca torda . 



13 



7 



17 



7 



8 





Fratercula arctica 



14 



7 



12 



7 



7 





Spheniscus minor 



13 



7 



14 



7 



7 





Eudyptes Van Diemen's Land . 



12 



7 



15 



6 



7 





Uria troile . 



13 



6 



12 



7 



8 





Plotus Novas Hollandiae . 



17 



5 



10 











— 



Pelicanus N. H. 



19 



5 



14 



7 



5 





Procellaria gigantea . 



12 



8 



14 



7 



7 





Puffinus fuligenosus 



12 



7 



12 



6 



7 





Tbalassidroma Wilsonii . 



11 



6 



12 



6 



6 





Diomedia exulans 



13 



8 



13 



7 



7 





Larus ridibundus 



14 



7 



12 



7 



7 





Sterna arctica . 



13 



6 



12 



6 



7 





Rhyncops nigra 



13 



6 



12 



8 



7 





Remarks. 



There is a great similarity among all the- Anserine in their osteological characters. 

 They may be distinguished, however, from the Cygnince by the much greater propor- 

 tionate length of the pelvis in the latter. The Colymbidce have the lengthened meta- 

 tarsus, and the xiphisternal process, besides the very much lengthened sternum and 

 narrow pelvis, to distinguish them from the AnatidcB. The Alcidce have the ribs pro- 

 jecting very far backwards, the keel of the sternum broad, and the hinder margin much 

 rounded and with very small fissures ; the pelvis is narrow for its posterior half, and 

 the palatine bones broad, and a strong spine projecting from the ilium on each side of 

 the caudal vertebrae. The Pelicanidce have generally the sternum very short, and in 

 many instances the furculum is anchylosed to it ; the keel also is seldom continued to 

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