ANATIDiE.] OSTEOLOGIA AVIUM. [PlECTROPTERINJE. 



Order XIII. NATATORES. 



Fam. 1. ANATIDJE. 



Subfam. Plectropterin^:. 



Plectropterus, Leach. 



Gambensis, Linn.* 



Cranium large, an oval knob on the forehead ; occipital crest and protuberance very 

 prominent. Palatine bones rather small for the size of the head, the outer edge much 

 inclined downwards, bifid at the hinder and lower extremity, narrowed and twisted 

 on their axis near the centre in an horizontal direction, expanded at their anterior 

 ends ; nostrils large ; inferior maxillaries much prolonged backwards ; behind the con^ 

 dyles a large flat process, with a spine at its base, which arises anterior to them, and to 

 which the maxillary muscles are attached. 



Sternum long, much broader at the anterior extremity ; keel of moderate depth ; 

 posterior margin with two large fissures nearly closed at their hinder extremity, the 

 hinder edge of central portion curved inwardly at the centre, lateral strips of bone 

 bounding the fissures not projecting beyond the central portion of the sternum ; 

 anterior edge of the keel straight, the point rather advanced, lower edge slightly 

 arched. Manubrial process wanting. 



Pelvis long, depressed in the centre for the posterior half; ischiadic foramen very 

 large ; obturator widest posteriorly, and gradually tapering forwards ; os pubis pro- 

 jecting beyond the ischium, and much curved inwards at the points. 



Ribs of moderate strength ; styliform processes long, and blunt at the extremities. 



Furculum flattened, the rami meeting • each other in a wide arch, a very slight 

 tubercle at their junction. 



Scapula strongj narrowed at the end to a blunt point. 



Wing-bones long ; humerus longer than ulna, armed with a long spur. 



Leg-bones very strong. 



Measurements. 



Tenths. 



Length of humerus 



Tenths. 



Length of femur ...... 38 



Length of tibia 67 



Length of metatarsus ..... 35 



Length of ulna ....... 60 



Length of metacarpus ..... 34 



* Having figured many of the skeletons of the Anatides before in my work on the Anatidce f I have not thought it 

 necessary to re-figure them in this work, 



203 



