MR. W. P. PYCRAFT ON THE BIRD’S WING. 
321 
tlie major coverts, we shall notice that they are closely bound to 
the remiges ; a pair to every retnex — the dorsal and the ventral. 
B 
Fig. 5. 
A. The upper surface of the left wing of an embryo Lapwing (Vanellus 
cristatn* ), showing the disposition of the feather papillae or rudiments of the 
future feathers. This is an example of a diastataxic or gap-winged form of 
wing, there being no remex between the fifth pair of major coverts in the 
adult. This figure shows that diastataxy has been brought about by a 
process of shifting of the remiges 1 — 4 and coverts 1 — 5 in each of the 
horizontal rows above remiges 1 — 4 Inasmuch as it has caused the fifth 
obliquely transverse run of coverts to come to lie between the remiges 
4—5, and the sixth row of coverts to move forwards, or outwards, to occupy 
the position of the fifth, the seveuth row of coverts to move forward to 
occupy the position of the sixth, and so on to the elbow-joint. 
The lower figure (B) is a diagram indicating the way in which the 
eutaxic wing becomes diastataxic. The “ intercalary” row is formed by the 
first row of minor coverts, not by the medium coverts, as indicated in the 
upper figure of this diagram. 
