88 Mr. J). A. Bannerman on rare Birds [Ibis, 



"worlied through what they term the soUtarius group of 

 Cuckoos in the Britisli Museum, and ])ublished their con- 

 clusions on pp. 642, 643 of ' The Ibis/ 1919. They remark 

 {J. c. p. 643) : " The relationship of the soUtarius group with 

 C. clamosus, the Black Cuckoo, which is also found all over 

 Africa, is very obscure, as is also the relatiousliip of 

 C. soUtarius and C. gahonensis. There appears to be a series 

 of intermediate forms (which has been called C jacksoni) 

 between C. clamosus and C. soUtarius. There is also a 

 series of intermediate forms (called C. mabirce) between 

 C. gabonensis and C soUtarius. It is possible that these may 

 be regarded either as three separate species intergrading in 

 certain areas, or as three species in process of evolution from 

 one form within those areas." I am not at all in agreement 

 with these conclusions, believing C. soUtarius to be a per- 

 fectly fixed race with very distinct young, 



Cucuhis gabonensis I believe to be also a fixed race 

 with distinct young, having a subspecies Cucidus gabonensis 

 mabiron. I shall deal with the status of C. clamosus and 

 C. jacksoni later. 



I have now the entire fine series of these forms contained 

 in the British Museum spread out before me in addition 

 to certain specimens kindl}' lent to nie, from Tiing by 

 Lord Rothschild and by Dr. van Someren from his private 

 collection. 



CUCULUS GABONENSIS GABONENSIS 



To deal first with Cuculus gabonensis gabonensis : we possess 

 fourteen examples in the British Museum showing the com- 

 plete change of plumage as explained by Mr. Bates (Ibis, 

 1911, p. 501). 



1. The first plumage is uniform black throughout (speci- 



mens Nos. 3898 and 3904). 



2. The second is the transitional stage, some of the barred 



feathers of the underparts and some of the barred 

 chestnut feathers of the throat are appearing amongst 

 the black feathers ; the glossy feathers are appearing 



