PLATE III 



DWIGHT PLUMAGE AND MOULT 



Photograph showing location of the Pterylse or Feather Tracts of 

 a Passerine bird. Natal Down or neossoptiles may be seen at the 

 tips of the juvenal feathers which are just breaking from their follicles. 

 The specimen a young Robin {Merula migratoria), five days out of 

 the egg, is photographed life size. 



Fig. i. . Superior Aspect of the Feather Tracts. 



1. Alar or Wing Tract. 



2. Humeral or Shoulder Tract. 



3. Capital or Head Tract. 



4. Dorsal or Spinal Tract. 



6. Lumbar or Thigh Tract. 



7. Crural or Leg Tract. 



8. Caudal or Tail Tract. 



Fig. 2. Inferior Aspect of the Feather Tracts. 



i. Alar Tract. 



3. Capital Tract (lateral view.) 



5. Ventral or Inferior Tract (dividing into two lateral 



bands). 

 7. Crural Tract. 



(352) 



