246 On the Structure of the Feather. [Ibis, 



It is curious that although the tegmeu appears on the 

 Pheasant, Blackcock, Grey Partridge, (Japercaiilie, Ptar- 

 migan (summer and winter plumage), and Turkey, it is not 

 found on the Domestic Fowl or Ked-legged Partridge. The 

 Partridge, Grouse, Blackcock, and Pheasant being so closely 

 allied, it is remarkable that, as far as my investigations go, 

 I should not have found the tegmen in the Red-legged 

 Partridge. It is beyond the scope of these notes to go 

 deeper into this subject, but it seems to me that the absence 

 or presence of the tegmen may well prove to be a diagnostic 

 character which so far has escaped the attention of syste- 

 matic ornithologists. 



The Red-legged Partridge has on the inner vane of the 

 primary a narrow ventral ridge with a smooth edge, while 

 towards the base of the outer vane the ventral ridge is larger 

 and has a strongly fringed edge;. 



Plate VI. fig. 4, with magnification of 150 times, shows 

 an example of this fringed edge. 



The Grey Partuidge has on the inner vane a tegmen with 

 smooth edge, and on the outer vane a ventral ridge more or 

 less fringed. 



Plate VI. fig. 5, with luagniHcation of 150 times, is given 

 as a sample of this type of fringe. 



The Grouse outer vane has a tegmen with a trace of 

 fringe here and there. The Pheasant outer vane has a 

 ventral ridge with rough edge and irregularly fringed. 

 The Blackcock outer vane has a tegmen with light fringe 

 commencing about half way from the base. The Caper- 

 caillie outei' vane has a tegmen with rough edge, with very 

 little trace of fringe. 



The presence ol' tegmen is not restricted to the primaries, 

 for I find it on the tail-feathers of the Grouse and Blackcock, 

 while in the Capercaillie it is most marked. It does not 

 appear on the tail-feathers of the Pheasant, Grey Partridge, 

 or Red-legged Partridge. 



Plate VII. fig. 1 was made to show the difference 

 in structure between the barb and tegmen. The dark 

 mottled portion is barb, and the lower and lighter portion 



