602 



Mr. F. E. Beddard on some Points in 



o£ the organ among birds. There is not, however, a com- 

 plete coincidence between the existence of a tracheo-bronchial 

 syrinx and the other two variable features in the anatomy of 

 the Cuckoos. It is true that all Cuckoos with the reduced 

 muscle-formula and a simplified ventral feather-tract have 

 the tracheo-bronchial syrinx ; but it is not true that all 

 Cuckoos with the full muscle-formula and the more com- 

 ])licated ventral pterylosis arc different also in the form 

 of their syrinx. In fact, in Eudynamis and its allies the 



Fio-. IG. 



Fi"-. 17. 



End of trachea and bronchi 

 of Hierococc.yx varius ; 

 ventral aspect. 



End of trachea and 

 bronchus of the same; 

 lateral aspect. 



syrinx is of the tracheo-bronchial type, while the formula 

 of the thigh is, as already stated, A B X Y with naturally 

 divided ventral pterylosis. On the other hand, no Cuckoo 

 is known whicli possesses tlic derived form of syrinx known 

 as " bronchial ^' (in which the attachment of the syringeal 

 muscles is much lower down the bronchi) that docs not also 

 possess the thigh-muscle formula A B X Y and lias not the 

 divided ventral tracts. It would be assumed, therefore, 

 that Hierococcyx^ having the reduced muscle-formula and 



