Plate III., Fig. 1, represents a Barb from a Pigeon's Primary extracted from 

 the plumulaceous structure at the base of the pennaceous. This photograph was 

 made with a magnification of 130 times. A large number of different piumu' 

 laceous barbs were examined and the barbules were found to vary from absolutely 

 smooth to a bamboo'like form called " knotty dilations." In the case of the 

 pigeon, as illustrated, these dilations take an angular shape which 1 have not 

 observed on any other feather in my possession. 



Plate III., Fig. 2, is a Barb cut from a Pigeon Primary at the point where 

 the pennaceous develops into the plumulaceous. On the right hand it will be 

 seen to be pennaceous and on the left plumulaceous. This photograph was 

 made with a magnification of 93 times. 



