236 



Genus Anas (Ducks). 



1263. The skeleton of a Duck (Anas boschas). 



The number of vertebrae between the skull and sacrum is 21, the last six of which support 

 ribs, which, save the first pair, are articulated by haemapophyses with the sternum. The last 

 three pairs of ribs are attached to the sacrum, the first two of which are articulated by haem- 

 apophyses to the sternum, that of the last being articulated to the preceding rib. 



Mus. South. 



1264. The skeleton of a male Musk Duck (Eiziura lobatd). 



There are 22 vertebrae between the skull and sacrum, of which the last seven support ribs : 

 the first of these is free and floating ; the six succeeding pairs are articulated to the sternum 

 by bony haemapophyses ; the last two ribs are attached to the sacrum, and by bony heem- 

 apophyses to the sternum. There are 1 1 caudal vertebrae. 



Mus. Gould. 



1265. The skeleton of a female Musk Duck (Biziura lobatd). 



There are 21 vertebrae, of which the last six support ribs: the first of these is free and 

 floating ; the succeeding five pairs are articulated by bony haemapophyses to the sternum ; 

 the last three pairs of ribs are attached to the sacrum, and, save the last, by bony haemapo- 

 physes to the sternum. There are 9 caudal vertebrae. The difference in the vertebral for- 

 mula is due to the more complete confluence with the sacrum of the vertebra answering to the 

 last dorsal in the male. 



The male is characterized by its greater size, more rugose upper mandible, stronger occi- 

 pital cristae, and longer proportional tail. The patella is remarkable for its large size and 

 angular form in both sexes. The outer of the three condyloid divisions of the metatarsus is 

 much raised, as in most of the Anatidae. 



Mus. Gould. 



1266. The skeleton of a female Sharp-tailed Duck (Oxytira australis). 



The great development of the procnemial and ectocnemial ridges indicates this species to be 

 a good diver. The breadth of the sternum, with two small notches posteriorly ; the strength 

 and span of the furculum ; and the strong incurved pectoral processes of the humerus, also 

 bespeak considerable powers of flight. There are 21 vertebrae between the skull and sacrum, 

 of which the last six support ribs : the first of these is free ; the rest are articulated to the 

 sternum by bony haemapophyses. The last two pairs of ribs are attached to the sacrum. 

 There are 8 caudal vertebrae. 



Mus. Gould. 



1267. The dried head of the Eider Duck (Anas mollissima). Hunterian. 



