1909] Beebe: Ecology of the Hoatzin. 51 



Amazona inferior. Est. do Amazonias, Rio Jurua, von 



Ihering (25). 



Santarem., Pelzen (33). 



Lower Rio Capim, Goeldi (21). 



Obidos, Sclater. 



Marajo Island, Rio Anabiju, Brigham. 

 The lower Amazon may thus be. considered as a center of 

 distribution from which the birds have slowly extended north- 

 ward into the Guianas and the Orinoco region; north-west to 

 Colombia ; west to Ecuador and Peru ; south-west to Bolivia and 

 south to the various tributaries of this greatest of rivers. Not 

 one of these localities is separated by a real water-shed, and all 

 are in communication with the Amazon, either by direct tribu- 

 taries, or by marshy itabos, or river- joiners. 



Part V — General Appearance. 



As far as general appearance goes, the name "Pheasant" is 

 not far amiss when applied to the Hoatzin. It comes closest in 

 general aspect to the chachalacas, but there is something strong- 

 ly suggestive of a peacock, especially in the carriage of the neck 

 and head. This is well shown in the positions of some of the 

 individuals in Fig. 11. 



My descriptions are based on 15 adult Hoatzins from the 

 following localities: Ciudad Bolivar (9) ; Guarapiche (1) ; Bo- 

 gata (1) ; Bolivia (1) ; Peru (1) ; Amazon (1) ; Abary, British 

 Guiana (1). 



Fig. 10. Beak of Hoatzin. 



There is apparently no distinguishing sexual character, and 

 remarkably little variation in size. However, the bird which I 

 collected in the Guarapiche, although adult, is distinct from all 

 the others in color, and if these characters should be found to be 

 constant in other individuals, the birds in this isolated locality 

 would form a distinct sub-species. 



