Plate Vlll., Fig. 1, is the sectional surface of seven Barbs (in their original 

 position) of a Turkey's Primary, magnified 22 times. Here the impossibility of 

 securing good definition over the whole had to be met with an average focus. 

 The distal and proximal barbules are seen interlacing above and from them 

 depend the seven barbs, each barb terminating in the curved form of tegmen 

 which should close the space between the barbs, but in arranging the subject it 

 was difficult to avoid disturbance. 



Plate VIII., Fig. 2. The above explanation applies to this illustration, 

 which represents a Pink-footed Goose's Primary. The barbules extend along the 

 upper surface and the tegmen appears as a flat cover on the lower side. In the 

 original position the construction was that of a series of tubes, but in order to 

 show the tegmen the barbs had to be slightly separated. 



Plate VIII., Fig. 3, is a section similar to the above from a Heron's 

 Primary. The section was cut outside the semi-tegmenous area. This photograph 

 was made to show an instance of " no tegmen." The barbules are seen above 

 and the vertical pointed barbs below, showing the absence of tegmen at the tips. 



It is curious that although the tegmen appears on the Pheasant, Blackcock, 

 Grey Partridge, Capercaillie, Ptarmigan (summer and winter plumage), and 

 Turkey, it is not found on the Domestic Fowl or Red-legged Partridge. The 

 Partridge, Grouse, Blackcock, and Pheasant being so closely allied, it is remarkable 

 that, as far as my investigations go, 1 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 

 systematic 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. 



