PHAETON INDICUS, A/ume. PHAETON &ZTHERIUS, Lin. 147 
Heuglin’s measurements and experience entirely confirmed 
my view. 
In Vol. V., p. 302, further particulars were given, and both 
Captain Butler and Mr. Davison from independent observa- 
tions confirmed my view of the distinctness of our Asiatic 
bird. 
Quite recently, despite all this, I find in a newly published 
work, P. indicus calmly treated as a synonym of P. a@therius. 
Under the circumstances, this is simply indefensible, and were 
it not that it may mislead others, who have not had the 
opportunity of examining both species, I should not have noticed 
it. As it is, a few additional remarks on the subject may 
perhaps prevent the further propagation of this misconception. 
I have now obtained and examined 23 specimens of the 
Asiatic species, some of which were shot in every month of 
the year, except April and September. 
I have also obtained, though with great difficulty, a speci- 
men of the Atlantic bird, procured, J believe, at Ascension 
Island. 
All the differences, in size of wing, length of central tail 
feathers, length of bill, size of tarsi, above pointed out, held 
good in all the 23 specimens of zndicus, and in the single 
specimen of @therius. 
Further, comparing the specimens, I notice the following 
additional differences. Whether invariably constant, having 
only one specimen of @therius, I cannot of course say ; but they 
are such as can be easily verified where numerous specimens 
of @therius exist. The differences in dimensions and _ tail 
development are alone sufficient to separate the two species, 
but these further differences, if constant, will conclusively 
demonstrate their distinctness :— 
First as to bills: Though longer, the bill in etherius is 
perceptibly slenderer, and has the angle of the gonys distinctly 
marked, whereas in indicus there is practically no angle. 
In every specimen of indicus, the bill was when fresh (and is 
so still) a dull red, more or less orange towards the base of 
the lower mandible, and there was, and is, a dark line 
distinctly marked along the entire commissure ; the bill is bright 
coral red, and there is no trace of this line in my @therius. 
Second as to plumage: [n indicus,.there is a distinct, though 
very narrow, black line from the nostrils to the gape along 
the margin of the feathers; there is nothing of this in the 
etherius before me. In atherius, all but the first two pri- 
maries hdive a conspicuous white margin to the outer 
webs, while in indicus, the fifth or in some birds the 
sixth, primary is the first to show this. In etherius the 
central tail feathers are black or dusky shafted for fully 
