Pygopodes — Golymbidse 3 



ORDER PYGOPODES. 



This order contains diving birds, and includes the 

 Grebes, Loons and Auks. The chief feature which they 

 have in common is the completely posterior position 

 of the legs, so that when resting on the ground the axis 

 of the body is more or less vertical and the whole of 

 the tarsus is often applied to the ground, while the tail 

 lends additional support. 



Other external features are — nostrils never tubular 

 or aborted ; wings short and rounded, never reaching 

 the end of the tail, which is always short and sometimes 

 absent ; tarsus compressed ; toes either webbed or lobate. 



IVEY OF THE FAMILIES AND GeNERA. 



A. No obvious tail-feathers (Colymbidce). 



a. Bill more or less slender and acute. 



a^ Bill longer than the head ; tarsus, cukaen and niiddle toe 

 about equal. ^chmophonis, p. 4. 



b^ Bill equal to or shorter than the head ; tarsus shorter than 

 the middle toe and claw. Colymbus, p. 5. 



b. Bill short, deep and strongly compressed, crossed by a black 



band. Podilymbus, p. 8. 



B. A tail of 18 to 20 short, stiS feathers {Gaviidce). Gavia, p. 10. 



Family COLYMBIDCE. 



Bill rather variable ; wing with twelve primaries, outer 

 ones rather narrow and falcate ; tail practically absent, 

 no obvious rectrices ; tarsus extremely compressed, 

 toes flattened and expanded into continuous lobes con- 

 nected with each other at the base by an interdigital 

 web ; hind toe slightly elevated, lobe free from the 

 other toes ; claws flat and nail-like ; head usually 

 with crests or ruSs in the breeding season ; plumage 

 thick and compact. 



b2 



