$70 Notices of Boohs. [May, 
thoroughness ; its only defect, in our opinion, is a disposition to 
indulge in irrelevancies, as may be seen in the essay on the Cat- 
bird, very pleasant reading though it be. 
The chapter on Swallows is admirable. The question whether 
certain individuals of the various species of this group, and of 
the swifts, do not occasionally hybernate, is discussed at great 
length ; and the author, whilst fully admitting that the vast ma- 
jority of these birds migrate, does not feel able to refute the 
evidence in favour of a minority passing the winter in northern 
climates in a state of torpor. The literature of this subject, 
chronologically arranged, extends to more than twelve pages, 
but curiously enough no mention is here made of Gilbert White, 
who repeatedly refers to the subjedt in his “ Selborne.” 
The architecture of the swallows is also considered at some 
length. The interesting fact is brought into due prominence 
that, with one possible exception, all the species have modified 
the structure of their nests in accordance with the novel facilities 
afforded by the settlement of the country. The case of the 
common European house martin is still more instructive, since 
within the last fifty years it has changed the shape of its 
dwellings, not in accordance with any modification in the cha- 
racter of the site selected, but simply with a view to increased 
convenience. 
Dr. Coues considers that the original and typical colour of the 
eggs of swallows, like those of hole-diggers in general, was a 
pure white, but that they have gradually become speckled as the 
nesting-habits of the bird have undergone modification. 
Swallow-shooting the author denounces with just severity, and 
he sympathises warmly with these amiable and useful birds in 
the defensive warfare they are now obliged to wage against those 
“ wretched interlopers ” the European sparrows, whom some 
wrong-headed acclimatiser has, it appears, rashly introduced into 
America. We hear with regret that the same blunder has been 
repeated in Australia. Whilst upon the subject of acclimatising 
it may not be deemed an unpardonable digression if we record 
our disgust at learning that an Expedition, which ere this has 
doubtless sailed from Australia to New Guinea, is about to intro- 
duce goats into that country — for the purpose, we presume, of 
destroying its magnificent flora. 
Space will not permit us to extend any further our notice of 
this work, which we must pronounce a sterling contribution to 
zoological science. 
