326 
HR. W. P. PYCRAFT ON THE BIRD’S WING 
and these are hardly likely to affect the growth and disposition 
of the feather papillae. 
One is tempted, however, at times to adopt the alternate 
hypothesis that diastataxy is an archecentric character directly 
traceable to the proto-avian wing. Reflection, however, robs this 
of its fascination, for it seems hardly likely that, in spite of the 
profound changes which have taken place during the evolution 
of the wing, the position of the original reptilian scales, from 
which the feathers have been derived, should have been preserved. 
If we admit, as indeed we must admit, that a very considerable 
shifting has taken place since the development of the feathers, 
we are landed in a still greater difliculty, for we should have to 
suppose that in spite of shifting and suppression, the existing 
feathers represent what is left of the clothing of the ancestral 
reptilian limb, scale for scale, and that the diastataxic condition 
of the wings of modern birds is due to the absence of a single 
scale in the exact position indicated by the “ missing ” quill. 
It seems to me more in accordance with the evidence to hold 
that the eutaxic wing represents the archecentric condition. 
Furthermore, it is probable that the primitive eutaxy is repre- 
sented only in the wings of the Palseognattue (Ratitse) — e.y., Rhea, 
Ostrich, and that the eutaxic wing of modern birds is a secondarily 
acquired character — a reversion to the primitive character — 
wherever it is met with. 
As further evidence, I venture to suggest that the presence 
of the feathers known as the carpal-covert, and remex may have 
some significance, inasmuch as since these feathers — representing 
a degenerate remex and its major covert — are found in the wings 
of both eu- and diastataxic forms among the Neognathae, they are, 
probably, in some way associated with the origin of diastataxy, or 
in other words, with the origin of the Neognathine avian wing ; 
for it must be remembered, it is here suggested that the eutaxy 
of the Neognathm is a pseudocentric character. 
For clearness sake, I have omitted the discussion of many other 
features in the pterylography of the wing in order that I might 
give the more prominence to the question of the origin and meaning 
of diastataxy. The causes which gave rise to this remarkable 
phenomenon are yet enshrouded in mystery. I commend the 
matter to the members of the Society. 
