Anitid^.] 



OSTEOLOGIA AVIUM. 



[Anatinjs. 



Dendrocygna, Sw. 



Arcuata, Cuv. 



Cranium. The space between the upper edges of the orbits much wider than in 

 Tadorna ; orbits very small. 



Pelvis. Ischiadic foramen small ; obturator very large, oval. 



Sternum similar in shape to Tadorna, but narrower in proportion to its length. 



Wing-bones much longer in proportion to the size of the bird. 



Furculum very broad and strong. 



Measurements. 



Tenths. 



Length of humerus 38 



Length of ulna 41 



Length of metacarpus 18 



Length of femur 23 



Length of tibia 35 



Length of metatarsus 22 



Length of sternum ...... 33 



Tenths. 



Breadth of posterior margin of sternum 14 



Breadth of anterior margin of sternum 14 



Depth of keel 6 



Length of head 34 



Breadth of head 10 



Length of pelvis 33 



Breadth of pelvis 1 2 \ 



Dendrocygna, Sw. 



Autumnalis, Linn. 



Very similar to the foregoing ; the palatine bones are, however, much narrower, the 

 sternum much broader on the posterior margin than on the anterior one, and the 

 obturator foramen is also much narrower. 



I have also the sternum of D. arborea, which is similar to the above. 



An as, Linn. 



Boschas, Linn. 



Cranium. The space between the upper edge of the orbits of moderate breadth; 

 orbits with two foramina, one placed over the other, at the hinder margin. Palatine 

 bones widened anteriorly ; interarticular bones very broad at their junction with the 

 palatine, and gradually tapering backwards. 



Sternum broader on its posterior margin than on the anterior; marginal fissures; 

 large manubrial process ; small triangular keel, deeper in proportion to the length of 

 the sternum than in Tadorna, the anterior point projecting far forwards, the anterior 

 edge slightly scolloped out. 



Pelvis similar in shape to Tadorna ; foramina of moderate size. 



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