602 
Mr. r. E. Beddard on some Points in 
of the organ among birds. There is not^ however, a com- 
plete coincidence between the existence of a traeheo-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 traeheo-bronchial svrinx : but it is not true that all 
Cuckoos with the full muscle-formula and the more com- 
plicated ventral pterylosis are different also in the form 
of their syrinx. In fact, in Eudynamis and its allies the 
Fig-. IG. 
Fig, 17. 
End of trachea and bronchi 
of Hierococeyx varms ; 
ventral aspect. 
End of trachea and 
bronchus of the same ; 
lateral aspect. 
syrinx is of the traeheo-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 which possesses the derived form of syrinx known 
as '^bronchial"" (in which the attachment of the syringeal 
muscles is much lower down the bronchi) that does not also 
possess the thigh-muscle formula A B X Y aud has not the 
divided ventral tracts. It would be assumed, therefore, 
that Hierococeyx^ having the reduced muscle-formula and 
