The back and sides of the head are covered with downy feathers of a silky brown and silvery gray, and the front of the neck with piliform feathers of a ruddy brown.    From Wordnik.com.  [Scientific American Supplement, No. 360, November 25, 1882] Reference

The head, which is relatively small, appears to be larger than it really is, owing to the development of the piliform tuft on the occiput, this being capable of erection so as to form a crest.    From Wordnik.com.  [Scientific American Supplement, No. 360, November 25, 1882] Reference