06 DICTIONARY OF BIRDS 
but a very little way in comparison with what we, or our successors, 
may hope to reach in years to come. Still we may feel pretty confident 
that we are on the right track, and, moreover, that here and there 
we can plant our feet on firm ground, however uncertain, not to say 
treacherous, may be the spaces that intervene. Now that geographical 
exploration has left so small a portion of the earth’s surface unvisited, 
we cannot reasonably look for the encountering of new forms of extant 
ornithic life that, by revealing hitherto unknown stepping stones, will 
quicken our course or effectively point out our path. Indeed, as a matter 
of fact, the two most important and singular types of existing Birds— 
Baleniceps and Rhinochetus—that in the latter half of this century rewarded 
the exertions of travelling naturalists, have proved rather sources of per- 
plexity than founts of inspiration. Should fortune favour ornithologists in 
the discovery of fossil remains, they will unquestionably form the surest 
cuide to our faltering steps; but experience forbids us to expect much 
aid from this quarter, warmly as we may wish for it, and the pleasure 
of any discovery of the kind would be enhanced equally by its rarity as 
by its intrinsic worth. Even the startling revelation of the group named 
STEREORNITHES has as yet done little except to add to our knowledge 
a number of ancient types! However, it is now a well-accepted maxim in 
Zoology that immature forms of the present repeat mature forms of the 
past, and that, where Paleontology fails to instruct us, Embryology may 
be trusted to no small extent to supply the deficiency. Unhappily the 
embryology of Birds has been till lately very insufficiently studied. We 
had indeed embryological memoirs of a high value, but. almost all were 
of a monographic character, and were only oases in a desert of ignorance. 
The same may be said of Morphology, so that a really connected and 
continuous series of investigations, such as was instituted by Prof. 
Firbringer, marked a new starting-point ; for it seems clear that hence- 
forth schemes for the Classification of Birds, as of other groups, will be 
divided into those which are based on Morphology, and those which are 
not—the latter falling year by year into disrepute. At the same time, 
with the greatest respect to Morphologists, it must be held that they, like 
other men, are bound by the rules of evidence and the exercise of common 
sense. Moreover, as the discrepancies between the schemes of different 
Morphologists shew, individual opinion will have to be reckoned with for 
some time to come. 
Birds are animals so similar to Reptiles in all the most essential 
features of their organization that they may be said to be merely an 
extremely modified and aberrant Reptilian type. These are almost the 
very words of Huxley in 1866,? and there are now but few zoologists 
to dissent from his statement, which by another man of science has been 
expressed in a phrase even more pithy—*“ Birds are only glorified 
Reptiles” It is not intended here to enter upon their points of re- 
semblance and differences. ‘These may be found summarized with more 
1 Of. Andrews, Rep. Brit. Association (Ipswich Meeting) 1895, pp. 714, 715; and 
Ibis, 1896, pp. 1-12. 
* Lectures on the Elements of Comparative Anatomy p. 69; see also Carus, 
Handbuch der Zoologie, i. p. 192. 
