CYPSELUS AFFINIS, Gray. 
In a letter to Mr. Strickland, of 8th November, 1851, Dr. Hart- 
laub makes the following observations :— 
“ Have you ever compared specimens of Gordon's West African 
Cypselus with the Indian O. affinis? and do you finally regard 
them as one and the same ‘species? I have now before me a fine 
adult specimen of the latter from the Himalaya, and several speci- 
mens of C. abyssinicus, Ehrenb. (Streubel in Isis, 1848) from St. 
Thomas's Island and the Gold Coast—which latter is certainly 
identical with Gordon’s bird—and cannot but take them for two 
very nearly allied but distinct species. The differential points are 
these—the African bird has the beak broader and in general a 
little largere; the African bird is itself decidedly larger than C. 
afinis ; the colour of the forehead is mich paler in C. affinis than 
in C. abyssinicus, and the same is the case with the tail, which is 
lighter coloured in afinis than in abyssinicus. Pray communicate 
to me your opinion on this point. If both birds prove to be iden- 
tical, then this instance of geographical distribution would be quite 
exceptional and extraordinary.” 
Upon receiving the above, we again carefully compared the Swift 
from Western Africa, which was procured by Dr. Gordon and re- 
ferred by us to the Indian species in “ Contributions” 1849, p. 5, 
with specimens of true C. affin’s sent from different localities by 
Jerdon, Blyth, Hodgson, and Cleghorn. In the first and third of 
Dr. Hartlaub’s differential points—the size of the bill, and different 
colour or shades of the forehead and tail, we can detect no diffe- 
rence. In the second point—the larger size of the African bird— 
the entire length of four Indian specimens is from 4.5 to 5.3; fork 
of the tail when slightly opened 3; wing 5 to 4.3, The entire 
length of the African bird is 5.4; fork of the tail when slightly 
opened 13; wing 5or5.1. The length of any skin is so dependent 
on preparation, that the very slight differences as above cannot 
be considered as important; and looking at the whole specimens 
placed together, there is more discrepancy in strength or robust- 
ness between those of India than. between any of them and the 
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