Plate v., Fig. 1, is a Distal Barbule cut from the Barb of a Golden Eagle 

 Primary, magnified 130 times. As it leaves the barb it resembles a flat strip of 

 ribbon, but at a short distance it takes a twist to the perpendicular. On the right 

 hand at the twist are two projections called teeth, the use of which does not appear 

 to have been defined. On the lower side the hamuli may be observed, as also 

 the filaments called barbicels. The twist to the perpendicular is obviously to give 

 rigidity and press the hamuli against the proximal barbules. 



Plate v.. Fig. 2, is a Distal Barbule cut at the base of the Hamuli from a 

 Barb of a Golden Eagle Primary, magnified 500 times. Here we see the forma- 

 tion of the hamuli clearly defined, and it may be recorded that the number of 

 hooks examined on various specimens of barbules seems to vary from four to six. 



Plate v., Fig. 3, shows a cluster of Hamuli on the Distal Barbules of a 

 Swan Primary, magnified 637 times. A few barbicels may be seen among the 

 hamuli. 



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