280 STRUCTURE AND CLASSIFICATION OF BIRDS 



with the sternum. The sternum may be fenestrated or 

 marked by posterior incisions. 



The atlas of Bhinococcyx ' is perforated by the odontoid 

 process ; Cll-Dl have hypapophyses in addition to the axis, 

 and two or three following, 012-14, have also catapophyses, 

 which on 14 ascend on to the heemapophysis. 



In Saurothera CIO has closely applied paired hsemapo- 

 physes. 



The modifications of the syrinx, the pterylosis, and the 

 leg muscles permit the family to be subdivided thus, the 

 subdivisions, as will be observed, corresponding to the 

 geographical range of the birds : — 



Subfamily I. Cuculinse. Syrinx tracheo-bronchial. Ven- 

 tral feather tract single. Muscle formula AXY + 

 a. Ventral tract single at commencement. 

 Cuculus 

 Chrysococoyx 

 Cacomantis 

 Coccystes (?) 

 h. Ventral tract double at commencement. 

 Saurothera 

 Diplopterus (?) 



.Old World. 



Piaya 

 Coccyzus 



-New "World. 



Subfamily II. Phoenicophainae. Syrinx tracheo-bronchial. 

 Ventral feather tract bifurcate. Muscle formula 

 ABXY+. 



Scythrops 



Eudynamis ■ Old World. 



Phcenicophaes 



Subfamily III. Centropodinse. Syrinx bronchial. Ven- 

 tral feather tract bifurcate. Muscle formula 

 ABXY-F. 



' In Scythrops there is a notch nearly completely converted into a foramen ; 

 in Evdyna/mis a notch less nearly converted into a foramen, also, in Ouwa and 

 Diplopterus. In Cucuhts and Saurothera there is a foramen. 



