PLUMAGE 495 



1833 brought out at Halle, where he was professor of 

 zoology, a Latin essay with the title " Pterylographia 

 Avium Pars prior." From the papers which he subse- 

 quently left at his death, Burmeister (laudably desirous to 

 complete the work which his predecessor had so well begun) 

 elaborated a comprehensive ''Pterylography." This being 

 translated from the German by the Ray Society in 1867, 

 has ever since been the standard work on the subject in 

 England. In that comprehensive work, the " Dictionary 

 of Birds," the subject of birds' feather-tracts is briefly 

 dealt with by Professor Newton (Introduction, p. 63), and 

 later on it is again treated of at greater length by Dr. Hans 

 Gadow (p. 744). This latter author distinguishes ten 

 principal tracts or areas from which the feathers of a bird 

 arise, of which the chief ones in the Steganopodes are the 

 spinal-tract, the ventral-tract and the neck-tract. All 

 these are of considerable width in Sulci, or Dysporus as 

 Nitzsch calls the Gannets, which is the only genus of the 

 Steganopodes figured, at any rate in the English edition 

 of his work.* 



Having stripped a Gannet of its plumage — a work which 

 to my unaccustomed hands was one of no slight labour — 

 and then rubbed off the down as far as it could be got rid 

 of, I endeavoured to verify the feather-tracts set forth by 



* " Pteiylography," Plate X., p. 150. 



