310 BULLETIN 15 3, UNITED STATES NATIONAL MUSEUM 



In studying the systematics of this species I have examined a 

 series of 32 specimens representing all three races. The literature 

 of this bird is unfortunately rather confusing, the chief bone of 

 contention being the variability in the amount of gradation in the 

 tail feathers. Van Someren ®^ has gone to the extreme view of 

 considering dmms and apatelius conspecific with each other but not 

 with fossei^ which he divides into two forms, the typical one, and a 

 smaller, eastern race, mosambiquus. Before critcizing his action it 

 is only fair to present his case in his own words. 



First of all, throughout a large part of the range of C. fossei fossei the form 

 clarus occurs as a breeding species, though elsewhere C. clarus is found where 

 C. fossei fossei is unknown. Now, as regards the supposed character of elonga- 

 tion of central tail feathers and graduation of the others in C. fossei, I find that 

 this is not a marked feature and not any more emphasized than in C. europaeus. 

 But in C. clarus and C apatelius the graduation is marked, the average length 

 of the central rectrices over the outermost being 30 and in some as much as 

 50 millimeters. 



I am therefore compelled to treat C fossei as a species with a small race in 

 Mozambique ranging into Tanganyika Territory, and also to treat C. clarus 

 as a species or parent race with one subspecies, C. c. apatelius * * *. i 

 have compared a large series in coming to these conclusions. Lord Rothschild 

 concurs in my opinion. 



Hartert ^^ writes that in his opinion apatelius must be considered 

 a subspecies of C. fossei but is not unmindful of Van Someren's 

 stand. 



After examining the specimens and perusing the literature, I 

 can not help but feel that what Van Someren has done was to arbi- 

 trarily pick out all the specimens with graduated tails and call them 

 C. clarus (or C. claims apatelius) and label those with no graduation 

 C. fossei (or C. f. ^nosamhiquus) . This may be one way of elimi- 

 nating the rather puzzling rectricial variations of these birds, but it 

 certainly is a high-handed one. It so happens that the series col- 

 lected by the Childs Frick expedition, in country where fossei most 

 certainly does not occur, and which are all definitely what Van 

 Someren would call G. clarus apatelius, present the same varia- 

 tions that are found in East Africa where, according to Van Som- 

 eren, two species, fossei and clarus, occur together. Only two con- 

 clusions, then, are possible — either that there are two species occupy- 

 ing the same country throughout in East Africa or that there is 

 but one species with considerable but not very unusual variation in 

 the diiferential length of the rectrices. The fact that otherwise 

 the two are identical precludes, I think, the probability of there 

 being two such closely allied specific entities geographically and 

 ecologically coincident over so enormous an area. The fact that 



^ Nov. Zool., vol. 29, 1922, pp. 85-86. 

 82 Idem, vol. 29, 1922, p. 402. 



