274 



STRUCTURE AND CLASSIFICATION OF BIRDS 



Of other cuckoos whose pterylosis has been studied } Caco- 

 mantis, Play a, Saurothera, Diplopterus, Coccuzus, Chryso- 

 coccyx, and Coccystes agree in most points with Cue til its. 

 But in the American genera Piay a, Diplopterus, Saurotlicrn, 

 and CWr//,:^.s-, the ventral tract is double from the very first 

 that is to say, in the mandibular region. 



A more complicated pterylosis characterises certain other 



FIG. 135. I'TKKYLOSIS OF Piay a cay ana. DOHSAL VIEW. (AFTER 



BEDDAKD.) 



cuckoos. Iii the genus Centropus the feathering upon the 

 throat is close and continuous, the tw r o ventral tracts diverg- 

 ing at about the junction of the neck and trunk. Each of these, 



1 BEDDARD, ' On the Structural Characters and Classification of the Cuckoos,' 

 P. Z. 6'. 1885, p. HIS; SHUFELDT, ' Contributions to the Anatomy of Geococcyx,' 

 ibid. 1886, p. 960. 



