776 REVIEWS. 
The three unpretentious volumes simply purport to be a “ hand- 
list of birds, distinguishing those contained in the British Museum ;” 
but this does not say what has been accomplished, nor more than 
hint at the immense labor involved. This astonishing compila- 
tion is really an epitome of ornithological literature. It under- 
takes to present and identify all the generic and specific names 
that have been proposed in ornithology from the Linnean times 
to to-day. And when we find that some five thousand generic 
titles, and over thirty thousand specific names, have been collated 
and identified, either as synonyms or as valid designations, we 
can appreciate what has been done. The index alone (which, by 
the way, takes up more than half the last volume) presupposes a 
familiarity with the literature of the science hardly to be expected 
in one man, to say nothing of the library work required in look- 
ing up authorities, and the mere clerical labor of transcription. 
But even this seems insignificant, when we recollect that two-thirds 
of the thirty thousand “ species” are synonyms, and that an 
equal if not greater reduction of the five thousand “ genera” was 
required ; that this great mass of bibliographical matter had to be 
thoroughly digested, the valid species to be sifted out and assigned 
to other proper sub-genera and genera, and then the load of sy- 
nonymy to be correctly distributed. Yet this has been approxi- 
mately accomplished. 
It is not within the bounds of possibility that all this should 
have been faultlessly done. In the first place, ornithological 
synonymy cannot now be completely disentangled ; in every fam- 
ily, and in every extensive genus, there are names that cannot 
be identified to everybody’s satisfaction. Secondly, the number 
of species cannot be fixed, owing to the well-known and unfortu- 
nate lack of agreement as to what shall be held for species and 
what for geographical or other differentiation. Supposing a man 
to have arranged before him every name that has been printed in 
ornithology, and to be personally acquainted with the bird upon 
which each one of these names was based ; yet then he would not 
be able to pass judgment that would not be contested or reversed 
by some other equally well informed ornithologist in at least one 
case out of ten. In such insurmountable difficulty as this, Mr. 
Gray has adopted the most judicious —in fact the only practicable 
—-course ; he gives doubtful species the benefit of the doubt. It 
was manifestly impossible for him to attempt, in his individ- 
