the Structure of Hierococcyx ^c. 605 



Cuckoos, containing tlic genera Eiidynamis, Sci/throps, and 

 Phcenicophaes, resembles the Cuculine series. F have already 

 indicated^'' the general likeness that exists between the 

 syringes in these three genera and that in the genus Cucu/ua. 

 There is, in fact, a very close resemblance ; but the full 

 G-arrodian muscle-formula and the complicated pterylosis 

 led me to place the group containing these genera midway 

 between the Cuculine and the Ceutropine series. I have no 

 leasons for doubting the correctness of that placing ; and I 

 may observe that Fiirbringerf seems inclined to allow this 

 arrangement, and to admit with me that Eudynamis and its 

 allies are perhaps to be looked upon as ancestral forms from 

 which the Cuculine series on the one hand and the Centropine 

 on the other are to be derived. We should, therefore, expect 

 to find in this group — or at least we should not be surprised 

 to find there — a syrinx of a rather more primitive style of 

 structure than in the hypothetically modified Cuculinfe. As 

 a matter of fact, what we do find in the Eudynamis group 

 are syringes shewing precisely the same characters as in the 

 t'uculine group. This, however, is no bar to the derivation 

 of the one series from the other. In my paper upon the 

 anatomy of Scythrops % I niade, as I find on re-examina- 

 tion of the syrinx of that bird, a slight error. I stated 

 erroneously concerning Scythrops that the intrinsic muscles 

 of the syrinx were attached to the second bronchial semi-ring. 

 But I now find that they were attached to the third of 

 those rings. 



Among the allies of Eudynamis we therefore find syringes 

 constituted upon two plans that are to be found in the 

 Cuculine series. But since the Phoenicophainte have some 

 claims to be regarded as ancestral to the Centropinse, we 

 should expect to find some hints of a Centropine arrange- 

 ment of the rings and muscles of the lower part of the 

 windpipe. It is one of the objects of the present communi- 

 cation to shew that there is a hint of a development into 



* P. Z. S. 1885, p. 172. 



t Unters. z. Morph. u. fSyst. d. Viigel (Ainsterdam, 1888). 



I P. Z. S. 18U8, p.44. 



