NUDITY OF THE HEAD OF THE ROOK. 161 
the Rook has of thrusting its bill into the ground in 
search of food. An extensive examination and com- 
parison of specimens had led me to observe that the 
nudity extends further and is more complete in some 
individuals than in others, that the more prominent 
and exposed parts are first deprived of feathers, and 
that short filiform processes, bearing a close resem- 
blance to new feathers enveloped in membrane, fre- 
quently occur on the less prominent and less exposed 
parts, particularly on the flaccid skin which occupies 
the angle at the base of the lower mandible. In 
addition to these facts, 1 may remark that an oppor- 
tunity had presented itself of inspecting a Rook 
whose mandibles were so greatly curved in opposite 
directions, and, consequently, so much crossed at the 
extremities, that it could not possibly thrust its bill 
into the ground; and the base of that organ and the 
anterior part of the head did not manifest the least 
deficiency of plumage. With such evidence in its 
favour, I was induced to adopt the popular hypo- 
thesis, which I now abandon in consequence of 
having recently proved by experiment that it is 
erroneous. 
Being supplied by George Davies, Esq., with two 
young Rooks, taken from a nest in his rookery at 
Cyffdy on the 17th of May, 1843, I put them 
into a large wooden chicken-pen, purposing, when 
they could take their food without assistance, to re- 
move one of them to a garden enclosed with walls, 
M 
