WHITE-HEADED SEA-EAGLE. 
Sangi, Celebes, Sula, Halmabera, Obi Major, Amboina, Burn, Timor and 
North Australia, where the dark shaft-lines are, as a rule, thin and scanty, or 
are quite absent, leaving the head, neck and breast pure white ; in New 
Guinea and the surrounding islands. New Ireland, Solomon Islands and Aru, 
these parts are apparently, in general, pure white, and this most eastern 
form of the species has received the name girrenem from Vieillot. But the 
species is so plentiful throughout its range, and the transition from the broad 
striped specimens of India to the white ones of New Guinea is so gradual and 
regular, that it is impossible to draw any distinct lines of demarcation between 
specimens from neighbouring localities ; and any geographical sections of 
the whole which have been called by distinct names are, by definition, only 
subspecies, or even subsubspecies. . . . 
“ Haliastur Indus arouses another question in nomenclature. If subspecies 
be distinguished by a trinomial, under what form of nomenclature are the 
forms which interconnect them to be spoken of ? In the present case, if the 
two extreme races only of H. Indus are treated of as subspecies, the main 
body of the species is made up of intermediate forms. Specimens from Java, 
which stands in character about midway between those of India and New 
Guinea, have been named intermedius by Gurney : and those of Celebes, 
which are again intermediate between the latter and those of New Guinea, 
were named H. indus var. ambiguus by the late Dr. Briiggemann ; but the last 
named, like those intermediate between intermedius and the typical indus^ 
cannot be regarded as more than subsubspecies : and if such a subdivision 
ever came into use four names must be employed for it. In such a case it 
is certainly much easier to remember the facts than the names which are 
intended to call them to mind, and the nomenclature employed would 
defeat its own purpose. Therefore we prefer to give no long names, but 
to designate the forms intermediate between the typical H. indus and 
H, indus — girrenera (the — is an error here) in the following manner : Haliastur 
indus — girrenera, with the remark that a long hyphen connecting the n^mes 
of two subspecies serves to designate the intermediate forms which connect 
them. It does not appear to be advisable to recognise H. indus intermedius 
as a third subspecies, since this is not aberrant but distinctly intermediate 
between the two extremes of variation in H. indus. . . . Better suited to 
the ornithological needs of the present day . . . are the signs > and < . . . 
We use them as follows : 
Haliastur indus > girrenera means that the specimen so indicated is 
more like the typical indus than girrenera (viz., ordinary birds from Ceylon, 
Sumatra, etc.) 
Haliastur indus < girrenera, more like girrenera than indus (Celebes, etc.). 
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