Genus — Z 0 0 N A V A . 
ZooNAVA Mathews, Austral Avian Record, Vol. II., p. 112, 
September 24th, 1914 . . . . . . . . . . Type Z. frartcica. 
Smallest Micropodine birds, with very small bills, very long wings, medium 
forked tails and minute feet, the tarsus unfeathered. 
The tip of the bill is minute, decurved, culmen ridge prominent, 
sides flattened ; under mandible small, tip slightly upcurved. The nostrils 
appear as elongate ovals, placed in a membrane-covered depression and lying 
parallel to the culmen edge, not to the ridge. 
The wings are very long, with the tip of three feathers, the second longest, 
the first equal to the third, the rest rapidly decreasing, all the feathers narrow 
and pointed ; the secondaries very short. 
The tail is comparatively long, almost half the length of the wing; it is 
well but not deeply forked, and the shafts are soft. 
The legs and feet are small : the tarsus naked, the covering entire, neither 
are the toes reticulate or scutellate. The hind toe is long and pointing back- 
ward, the remaining three toes all pointing forward. 
The present genus comprises the birds classed in the Catalogue of the Birds 
in the British Museum and generally since under Collocalia, but the type of 
that genus is H. esculenta Linne. This latter is a much smaller, differently 
coloured bird with a smaller (comparatively) bill, a shorter tail, not forked, 
scarcely emarginate and even more minute legs and feet. The coloration 
separates this as a different evolution product, as in the Zoonava coloured species 
three generic types can be distinguished ; a larger form with a long even tail 
and a feathered tarsus. This has been named Aerodramus by Oberholser 
{Proc. Acad. Nat. Sci. Philad., 1906, p. 182), the type being Collocalia innominata 
Hume. 
The other is hereafter named, being the species Chcetura grandidieri, which 
was placed in the genus Chcetura because the tail-feathers have their shaft 
stiff and the tips projecting like needle-points. Otherwise in every detail of 
structure and coloration it agrees with the type of the present genus. 
The order comprises a series of long-winged, small-footed birds which 
are generally recognised at sight, but which may not be homogeneous. Anato- 
mical investigation has shown that the superficial likeness covers distinct forms, 
and it is possible that later the group may be split up. The bill is generally 
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