324 University of California Puhlicatians in Zoology [Vol. 13 



inni. and usually a little over 0.8 nun. In the ai^ette-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 pi. 27, figs. 55a-d) and possibly 

 Cariama (p. 352, and pi. 27, figs. 56a. and &) are probably nearly 

 related to the Ardeae. Cursorius, family Glareolidae (p. 356, and 

 pi. 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, in which the down is dark gray, the pigment is 

 absent only at the nodes (pi. 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. Eurypyga, 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 epiphyologieal characters: 



(1) Plumules confined to apteria. 



(2) Aftershaft present. 



(3) Powder down present. 



(4) Lores 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 

 blunt triangle; booklets usually 5, only 3 or 4 progressively dimin- 



