460 STEUCTURE AND CLASSIFICATION OF BIRDS 



Tachyeres, are hardly if at all to be distinguished anatomically 

 from the typical geese and ducks. Our knowledge of the 

 muscular structure of this group of birds is mainly dae to 

 FuEBBiNGBE, who has illustrated the fore half of the body 

 by two double plates referring to Anser cinereus. 



An interesting duck character (also, however, found in 

 Colymbus, Tinami, and some Galli) is the meeting of the two 

 great pectoral muscles over the carina sterni. In Mergus 



Fig. 217 Biceps Femokis of Duck (Bi), to show its 



Eelations to Gasteocnemius (aftek Weldok). 



merganser, for example, they blend for. a space of half 

 an inch. 



There is a biceps slip present,' and this has at least 

 sometimes a peculiar arrangement, which is remarkably like 

 that of the Colymbi. In Anser cinereus Fuebringbb 

 figures the biceps slip as attached in the ordinary way to 

 the tendon of the tensor patagii longus ; but before it is thus 

 attached it- gives off a slender tendon, which — exactly as in 

 the Colymbi — runs over the patagium and is inserted on to 

 the fore arm in front of the broad and diffuse tensor patagii 

 brevis tendon. 



In Anas Furbeingbb figures this tendon as joining the 



' Not in Cygnus BeioicM. 



