324 University of California Publications in Zoology ‘Vou. 18 
mm. and usually a httle over 0.8 mm. In the aigrette-like feathers of 
Bubuleus ibis of Europe there are only 11 proximal barbules and 
14 distals per millimeter, and they never exceed about 0.57 mm. 
in length. These barbicels are even more rudimentary than in the 
true American egrets. 
Eurypyga (see p. 352, and pl. 27, figs. 55a-d) and _ possibly 
Cariama (p. 352, and pl. 27, figs. 56a and b) are probably nearly 
related to the Ardeae. Cuwrsorius, family Glareolidae (p. 356, and 
pl. 28, figs. 60a-c), also appears to be most nearly related to the 
Ardeae. 
c) Down 
The down barbules in Ardea are long, reaching a length of 2 mm. 
or more, being filamentous and very slender, with slightly enlarged 
nodes, and pigment uniformly, or almost uniformly, distributed. 
Minute prongs present at nodes on more distal portion of barbules. 
In Botaurus, 1 which the down is dark gray, the pigment is 
absent only at the nodes (pl. 34, fig. 100). 
d) Relationships 
The Ardeae, or at least the Ardeidae, seem to form an end 
branch from a ciconiid stem, being considerably more specialized 
than the Ciconiae, and apparently not giving rise to any other 
orders or suborders. Hurypyga, and to a less extent, Cariama, both 
ordinarily classed in the Gruiformes, have a feather structure which 
is so heron-like that the possibility of their inclusion in the Ardeae 
is strongly suggested. Cursorius likewise has a structure which 
strongly argues for its inclusion in this group. 
e) Summary 
The typical Ardeae have the following epiphyological characters : 
(1) Plumules confined to apteria. 
(2) Aftershaft present. 
(3) Powder down present. 
(4) lLores naked. 
(5) Distal barbules nearly twice as numerous as proximals. 
(6) Distal barbules of remiges with small base, with large, 
leaflike ventral teeth, so shaped and arranged as to form a large 
cr 
blunt triangle; hooklets usually 5, only 3 or 4 progressively dimin- 
