322 NOTES AND COMMENTS [NOVEMBER 
separated from its remex (the fifth), and comes to lie, in the adult, 
quill-less between quills—the fourth and fifth. The place of the fifth 
oblique row of coverts is now taken by the sixth which runs outwards, 
that of the sixth by the seventh, and so on inwards to the elbow, thus, 
each obliquely transverse row from the wrist inwards moves forward 
one place, as also do the remiges (1-4); the remainder appear to be 
stationary. Thus does the eutaxic wing become diastataxic. 
Numerous figures of embryonic wings leave little doubt that this 
interpretation of the mystery is correct; what we want to know is 
“Why this shifting ?” 
Mr. Mitchell, in the pterylogical section of his paper claims to 
have proved that the diastataxic wing is architaxial, and not the 
eutaxic, as is held by Mr. Pycraft. He endeavours to support his 
claim by demonstrating the transition from diastataxy to eutaxy in the 
wings of certain pigeons—upon which group the whole of his observa- 
tions are based. 
This transition seems to be brought about by a shortening of the 
wing, and the obliteration of the usually more or less marked gap 
between the fourth and fifth remiges. But more than this; the crux 
of his paper rests upon the identity of certain covert feathers lying in the 
interspace between the fourth and fifth remiges just referred to. In 
certain of the pigeons he has examined, as in many other birds, the 
median coverts lie in the interspaces between the remiges. As a 
consequence, in the diastema between remiges 4-8 we have a major 
covert lying between two median coverts. In some pigeons two of 
these three feathers disappear, and the wing, according to Mr. Mitchell, 
becomes eutaxic. Assuming that the remaining covert is of the median 
series he has proved his contention. If, however, as he himself 
suggests, it is a major covert, his contention is only partly true. We 
have a pseudo-eutaxy. This last point is one of very considerable 
importance, for it may happen that, after all, the apparently eutaxic 
forms which occur amongst diastataxic groups may prove ultimately to 
be pseudo-eutaxic. At least this must be so, if we define diastataxy 
as that form of wing lacking a secondary remex from between the fifth 
pair of major coverts. This interpretation would be quite in harmony 
with Mr. Pycraft’s paper. It is to be hoped that further research will 
be made in this part of the subject. 
Immunity acquired before Birth. 
Ir is of interest to students of heredity to note the observations of 
Messrs. Béclére, Chambon, Ménard, and Coulomb (Comptes Rendus 
Acad. Sci. Paris, exxix. 1899, pp. 235-37), on sixty-five mothers 
and an equal number of newly-born children. The results make it 
