328 Proceedings of the Royal Physical Society. 



been repeatedly compared with freshly-killed examples. To 

 reduce it to a short description is next to an impossibility. I 

 would here again remark tliat the line of separation between 

 the Marginals and the Minors in the Pigeons baffles all 

 attempts at definition. The two groups of feathers merge 

 into each other by the most imperceptible gradations in the 

 present case ; although in most other birds there is not much 

 difficulty in drawing a line of demarcation between them. 

 Compare, for example, the wing of the Tern (Fig. 20) or that 

 of the Wild Duck (Fig. 14), or again that of the Skylark 

 (Fig. 4) with the Pigeon's wing, and note the ill-defined 

 character of the feature in question in the last case. 



The Domestic Pigeon is usually chosen as a convenient 

 and easily-obtained type of bird structure in general. It 

 may be so in some respects ; but its wing, certainly, is any- 

 thing but typical, and should on no account be selected to 

 illustrate the arrangement of the covert feathers. 



In comparing the effects of the faulting due to the absence 

 of the fifth cubital remex in the Pigeon with the same 

 phenomenon in, say, the Ducks, it will be noted that, 

 whereas the feathers are faulted heyond the general limit of 

 the coverts in the Ducks, etc., they are drawn up, or shortened 

 in the case of the Pigeons. In other respects the Pigeon's 

 wing forms as good an illustration of the value of the external 

 characteristic here specially discussed, as is afforded by such 

 birds as the Ducks, the Parrots, the Acciptrines, etc. 



It should be noted that in the Columbine style of wing 

 coverts the Medians, or those next above the Majors, exhibit 

 distal overlap from one end of the series to the other. 

 Distal overlap, indeed, characterises nearly the whole of the 

 feathers in this group. 



In the Pigeon Grouse (Pteroclid^) this last-named 

 feature is carried to excess. I do not see anything whatever 

 in the style of the wing coverts in this group to warrant its 

 being separated far from the true Pigeons. 



IX. The Gralline Style. — This modification is well 

 represented by the wing of the Golden Plover (Fig. 18), 

 which has already been mentioned as a central type for the 

 whole of the EuoenitiitE. In this winu- it will be noticed 



