370 REVIEWS. 
exact relations that subsist between the average intensity of col- — 
oration of the birds that collectively inhabit the regions so defined. 
We are gratified to find ourselves endorsed by Mr. Allen’s inves- — 
tigations, as appears from the following paragraph :— ) 
“ I had long suspected that hygrometric conditions had much to — 
do with local variations w color in oe at a the same spe- 
cies, but I was not a little surprised when I ¢ compare the 
known areas most prolific of dark or light toca rs with rain- 
charts — which may be assumed as indicating relatively the hygro- 
metric conditions of different regions — to find the distribution of 
the light colored races so strictly coincident with the regions of 
espe ell mean annual rain-fall, and the dark forms with those 
of maximum mean annual rain-fall, as seems to be the case. 
a has he ence pete more to do with climatic variation 
than solar intensity.” (p. 240.) 
Part III concludes with a vehement protest — certainly not 
lacking in the force that comes of conscientious and earnest be- 
lief—against the custom of naming forms, however distinct, that 
are found to intergrade; and at the risk of protracting this no- 
tice beyond due bounds, we cannot, in justice to our author, refuse 
to follow him further, although by so doing we must defer (pet 
haps to take up in another connection), what we should wish to 
say respecting Part V, in which the several bird-faunz of eastern 
North America are defined. 
Mr. Allen undertook a laborious and not entirely grateful taste 
and has won enviable laurels in its execution. It is so discourag> 
ing to the strongest swimmer to feel that he is breasting the tide- 
of nearly universal opinion, that moderate success must be corres- 
pondingly acceptable. If it be something to deserve thorough 
criticism it is more when close scrutiny detects nothing worse than 
indiscretion. From the nature of his’ task, he was peculiarly €x- 
posed to the danger of over-doing; and in using the old maxim, — 
ne quid nimis, we indicate the pith of what adverse criticism We 
feel compelled to make. In contributing invaluable material, care- 
fully elaborated and forcibly presented, Mr. Allen seems neverthe- 
less to have viewed his theme through the medium of enthusiasti¢ — 
iconoclasm so refractive that he has lost some of his bearings, and — 
reached a position so extreme, that we fear ornithologists must — 
able and his conclusions untenable. And what does he offer — 
instead of the idols he deposes? After being shown what is not & 
