XXlll 



Sometimes^ however, as sliOTvn in the case of the female 

 Sparrow- Hawk before alluded to^ the 6th cubital covert is 

 shorter than the 5th or the 7th, between which it has its 

 position (figs. 2, 2», pp. xii, xiii). This is not, as might be 

 imagined, a mere variable or spontaneous occurrence, but is a 

 constant feature in many families of birds, particularly those 

 which are " aquintocubital.''' The same peculiarity obtains 

 in the 9th cubital covert, at least in all the larger Waders, 

 the Herons, and Cranes which I have examined up to the 

 present. This tends to show that it is not a mere chance, 

 but is the outcome of some definite arrangement. 



These shorter major coverts (I am alluding to the dorsal ones 

 only on the present occasion) distinctly mark the corinnence- 

 ment of a series. The covert Avhich I call the "'carpal covert " 

 commences the series to the 5th and includes the latter — 

 making a total of 6, which together form ih.e first group 

 of the cubitals or secondaries. The 6th. marks the com- 

 mencement of the second group, extending to the 8th and 

 inclusive of the latter: this series consisting of 3 coverts. 

 With the 9Lh commences the third group, which embraces 

 the remainder of the cubital coverts belonging to the pos- 

 terior portion of the ulna. 



The better to comprehend my argument, these coverts 

 are coloured red in the Plate accompanying this paper 

 (figs. 1 & 3), showing their actual positions on the wing, 

 and representing the condition and limits of all three 

 series"^. 



Fig. 1 represents the wing of a bii'd, in which the 5th 

 cubital remex is absent, but its natural position is indi- 

 cated by a quill emphasized by transverse lines, so as to 

 show the entire normal number of cubitals, which varies, 

 according to Sundevall, from 9 to as many as 40 or even 

 more. 



* Ad analogous case, — not insisted upon in the present paper, to avoid 

 complica,tion, — can be seen ou the mauus of every uird"s wing-, -v^-Iiere the 

 series of major coverts equally couiruence with a short covert either 

 belonging to the 10th or 11th (remicle') flight-feather. In tig. 3 of the 

 diagram, the actunl position of the remiges may be seen in their relation 

 to the respective bones which carry them. 



