THE COMMON HERON. 



Ardea rrivEREA. Linn. 



In the genus Ardea, now limited to the Herons and 

 Bitterns, the bill is considerably longer than the head, 

 sharp at the point, straight or very slightly curved, 

 compressed laterally, cleft to the very base, and fre- 

 quently armed at the edges w^ith sharp denticulations ; 

 the upper mandible is marked on either side by a longi- 

 tudinal groove, in which the linear nostrils are perforated 

 near the base of the bill ; from the bill to the eyes 

 extends a space destitute of feathers ; the tarsi are lono- 

 and covered with large scales ; the legs naked for some 

 distance above the knee-joints; the toes long and 

 slender, the outer one united to the middle by a mem- 

 branous expansion, and the posterior attached so low 

 down as to allow of its resting its whole length u\x>n 

 the ground ; the anterior claws of moderate length. 



