186 MR. F. E. BEDDARD ON THE CUCKOOS. [Feb. 1 7, 



organ. In Geococcyx, Centropus, Pyrrhocentor, and Coua * the 

 syrinx is somewhat intermediate between the bronchial and the 

 tracheo-bronchial, but on the whole appears to me to present more 

 resemblances to the former. 



The continuation of the membrana tympaniformis up to the bifur- 

 cation of the bronchi, and the presence of a well-marked pessulus 

 undoubtedly are points which characterize the tracheo-bronchial 

 syrinx; on the other hand, the extreme narrowness of the membrana 

 tympaniformis in the anterior half of each bronchus, and its sudden 

 widening out at that bronchial semiring upon which the intrinsic 

 muscles of the syrinx are attached, indicates that the syrinx of these 

 genera is only separated by a very small interval from the bronchial 

 syrinx of Orotophaga. 



A complete closure of the already very narrow interval separating 

 the inner ends of the anterior bronchial semirings would bring 

 about a syrinx entirely indistinguishable from that of Crotophaga ; in 

 the ordinary tracheo-bronchial syrinx the membrana tympaniformis 

 is widest anteriorly, and, if anything, diminishes posteriorly. 



Guira and Crotophaga further present an agreement with each 

 other in having eight rectrices instead of the ten which characterize 

 all the other genera of the family known to me ^. 



The tracheo-bronchial syrinx of Endynamis and Phcenicophaes, 

 combined with the Centropine characters exhibited in the pterylosis, 

 appear to me to necessitate their separation both from the Cuculine 

 and the Centropine forms. The muscle-formula of these two 

 genera (seep. 170) is complete; and so far they agree with the 

 Centropine and differ from the Cuculine genera ; they should perhaps 

 form a third subfamily equivalent to either of the other two. 



The following table of classification will serve at least as an 

 abstract of the facts contained in the present paper, and of the 

 conclusions respecting the mutual affinities of the different genera, 

 to be derived from a study of these facts. I do not of course 

 pretend that as a system of classification it will be permanent ; but it 

 may at any rate be an assistance towards a proper classification, 

 which can only be drawn up when all the genera have been 

 thoroughly studied. 



* I have not myself examined Coua, but I possess sketches of its syrinx 

 drawn by Mr. Garrod from specimens lent to him by M. A. Milne-Edwards. 

 It is but fair to my predecessor to mention also, that several of the other 

 syringes described in the present paper have been carei'ullj' drawn by him. 

 The woodcuts which illustrate this paper are not, however, copied from Mr. 

 Garrod's sketches, which only came into my hands after the woodcuts had been 

 already drawn by Mr. Smit. 



^ Mr. Sclater particularly associates these two genera in his ' Catalogue of 

 American Birds,' p. 320. 



