AND THE PROBLEM OF DIASTATAXY. 
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body, or away from the tip of the wing. For convenience sake, 
the wing feathers are divided into (A) remiges or quills, and 
(11) tectrices or coverts. 
The remiges are the large feathers seated along the hinder border 
of the wing, which sustain the flight. They constitute two series, 
(A) the primaries or metacarpo-digitals, from their position on 
the hand; and (B), the cubitals or secondaries, which rest, by 
their bases, upon the fore-arm. 
The coverts are distinguished as the major, median, minor, ami 
marginal coverts. They clothe both the upper and under surface of 
the wing in all except the flightless Struthious birds, in which the 
tinder surface of the wing is bare. For the moment, however, we 
will confine our remarks to the dorsal aspect of the wing. Of the 
major and median coverts there is never more than a single row. 
The number of rows of minor coverts varies from one to five or six. 
The number of marginal coverts is also variable. 
In some birds all the coverts of the upper wing surface have 
a distal overlap. In the majority of cases, however, the minor 
coverts have either a proximal overlap throughout, or the inner 
feathers have a distal and the outer a proximal overlap. 
The figure illustrating this part of our subject will show at 
a glance the different forms of overlap, and will also point out how 
important a bearing it has on questions of systematic zoology, and 
for such artists and draughtsmen who esteem accuracy worth 
attaining. 
It will be impossible, in studying the overlap of the wing feathers, 
to escape noticing the fact that in a very large number of wings 
there are indications of disturbance having taken place in certain of 
the rows near the carpus or wrist ; the major, median, and minor 
coverts being all more or less markedly involved. The disturbance 
in question most generally takes the form of a break in the con- 
tinuity of the rows, suggesting, as Mr. Goodchild has aptly described 
it, a process of “ faulting.” Thus, the first four major and median 
coverts appear to be markedly longer than the remainder of the 
series to which they belong ; above the lengthened median coverts 
there appears to be, what has been called a supplementary or inter- 
calary row, and beyond this all is normal (Fig. 4 A). 
If we now endeavour to solve this mystery, and begin by raising 
