288 FOSSIL, BIRDS 
chiefly in forms confined to islands; and this is a result in full 
accordance with that already attained in the foregoing treatise on 
EXTERMINATION. In Europe a not very remote glacial epoch 
has left its indubitable trace in the former southerly extension of 
some forms whose home is now in more northern districts. The 
comparatively-few known Pliocene Birds are mostly referable to 
existing genera, though the majority of the species are extinct ; 
but in the Lower Miocene we meet with a considerable number of 
extinct genera; while, both here and in the Upper Eocene, the 
occurrence in Europe of genera either identical with or nearly 
allied to those which now inhabit only the tropics or lands lying 
even further to the southward is particularly instructive. Some 
of them are at present peculiar to the Ethiopian Region, and among 
these are especially to be noted Laurillardia, Psittacus (PARROT), and 
Serpentarius (SECRETARY-BIRD), With perhaps Cryptornis—a supposed 
HoRNBILL, and Necrornis—referred to the PLANTAIN-EATER. 
Others have their modern representatives in Asia, as Gallus 
and Phasianus; while others again have now a still wider range, 
though no longer occurring anywhere in the temperate zones, 
as Collocalia (Swirt), Leptoptilus (ADJUTANT), and, perhaps most 
suggestive of all, TRoGON, for the Family to which it belongs, 
though inhabiting both the Ethiopian and Indian Regions, is now 
more largely developed in the Neotropical Regions than elsewhere. 
This last case is in some measure analogous to that of the Tapiridx 
among Mammals, though no African Tapir is known. But in a 
general way all the lessons which Fossil Ornithology so far teaches 
seem to be in perfect harmony with what we learn from a study 
of Fossil Mammals; and, when palzontologists generally come to 
admit the fact, which some of their leaders have long since recog- 
nized,! that their study, though one of infinitely great meaning to 
the geologist, is but a branch of Zoology, no one can doubt of 
the valuable results that will follow from their co-operation. 
But letting this pass, it is important to notice that already 
in the Lower Miocene, if not in the Upper Eocene periods, 
there is sufficient evidence to shew that many of the chief groups 
of Birds as we now know them had been already established, and 
1 The views of the elder Agassiz on this point are notorious ; those of Prof. 
Alphonse Milne-Edwards were declared prior to the publication of his great 
work, which itself is a perpetual witness of their truth. Prof. Huxley many 
years ago in a speech, which though never fully reported is well remembered 
by some of those who heard it, most rightly asserted that ‘‘ Paleontology is 
simply the biology of the past; and a fossil animal differs only in this regard 
from a stuffed one, that the one has been dead longer than the other, for ages 
instead of for days” (Jbis, 1866, p. 418). The present petrified condition of 
some geologists requires a life-imparting impulse, and they—be it said with all 
due respect—need bringing into touch with those who would gladly accept their 
assistance or even their guidance.—A. N, 
