248 



PODICEPS. 



seem to render a tail unnecessary, that organ being reduced 

 to a diminutive tuft of" downy featliors. The extreme com- 

 pression of the tarsus, and the arrangement of the toes, which 

 fohls so as to have Httle more breadth than it, enable the foot 

 to be brought forward without receiving almost any opposi- 

 tion from the water. The tibio-tarsal joint is so constructed 

 that the tarsus when extended is in a right line with the 

 tibia, and on being contracted continues in the same plane 

 until it comes to form a right angle, but then inclines more 

 and more outward, so that it can not only be bent back so as 

 to be parallel Avith the tibia, but to extend far beyond it, and 

 thus the sweep of the paddle is very much increased, and to 

 facilitate tliis the tibia rotates on the femur. In swimming, 

 these birds propel themselves entirely by the feet, and in 



diving never use the wings. When molested they seldom rise 

 on wing, but escape by passing into the water. They rise 

 heavily, but have a rather rapid, direct flight, performed by 

 regular beats, and when alighting on the Avater, come down 

 with great force, gliding along its surface until the momen- 



