AFRICAN LONG-TAILED NIGHT-JAR. 67 
with those words which pass from mouth to mouth, 
like current coin, through the republic of science. 
The same reasons, however, do not apply to the 
vernacular name; and, therefore, while we retain 
Caprimulffus, we may very well substitute the old 
English name of Night-jar for that of Goat-sucker. 
It is only of late years that two or three of the 
most remarkable forms in this intricate family have 
been detached under separate names; while the 
great mass of the species have been left in the same 
state as they were in the days of Linnaeus. This, 
indeed, has been the case with more than one 
family, but in the present it has been productive of 
peculiar confusion and perplexity. W e have already 
had occasion to advert to the drongo-shrikes, as 
■ being one of those groups wherein a close similarity 
of colouring pervades nearly all the species, and 
the remark is still more applicable to the family 
before us. We might almost say, that in regard to 
colour, if a person has seen one species of Capri- 
mulffus, he has seen all. There are, it is true, 
trifling variations, hut these are sometimes so slight 
that none but an acute ornithologist would detect 
them ; while, from their very nature, they are so 
. difficult to describe, that the most laborious descrip- 
tions fail to convey these differences to the mind of 
the reader ; the different shapes of the marks, band, 
and spots, the manner in which they are blended, 
■ and the diversity of tints under which the different 
colours of brown, grey, rufous, and whitish appear, 
often upon a single feather, in these party-coloured 
