102 DICTIONARY OF BIRDS 
might stand midway. Future discoveries, which one may in all prob- 
ability expect, will still more efface this artificial boundary (p. 1564).1 
The great novelty of Prof. Fiirbringer’s treatment of the Ratitz is not 
merely denying their existence as a distinct Subclass, for that had been 
done before? ; but his demonstration, for it amounts to that, of their 
being the retrograde descendants of volant ancestors, and moreover his 
opinion that they diverged at different epochs, so that the several groups 
which now exist are not homogeneous but each had an independent 
pedigree. This not only carries to an extreme the views first enunciated 
by Huxley, who pointed out that each of the existing Ratite groups was 
equivalent in rank to what is commonly deemed an “ Order” among 
Birds (though he himself refused them the title), but it also involves an 
acceptance of the doctrine of Isomorphism, to consider which would lead 
us quite beyond our present limits, and therefore must be here let alone? 
It should be said, however, that this conclusion seems to have been slowly 
and almost reluctantly adopted by Prof. Fiirbringer, who in the fairest 
way states the objections that may be taken to it, though finally over- 
riding them with the result given above* Among the great merits of 
this great work are the representations of a genealogical “tree” shewing 
the descent of Birds not only vertically, and that on two sides, but also 
horizontally at three different epochs. It is unfortunately impossible 
here to reproduce these designs, and as without their aid no correct 
impression of his Classification could be conveyed, it seems better to 
abstain from any attempt to set it forth imperfectly in a linear form, 
1 The expectation expressed by Prof. Fiirbringer in this last sentence is a truism 
and need not alarm any true believer in Evolution, since as elsewhere observed 
(GEOGRAPHICAL DISTRIBUTION, page 344) it is obvious that if all creation, past and 
present, stood before us no lines of demarcation could be drawn, ‘The taxonomer 
has to judge by the comparatively small number of forms left to us, and between 
them are gaps, sometimes (so to speak) narrow cracks at others wide chasms, to fill 
up which is often beyond the power of imagination, though we know that filled they 
once were. Those gaps form not only convenient but the sole means of marking off 
groups of beings, whether we call them species or sub-kingdoms. Experience teaches 
us to expect that in time we shall partially know how some of these gaps were filled. 
2 Jt has been likened to Owen’s treatment of them, but is really very different. 
Owen, having formerly recognized an Order CuRSORES (by no means equivalent to that 
of Illiger), in 1866 declared (Anat. Vertebr. ii. p. 12) it not to be natural, which is 
quite true if in it are placed the heterogeneous forms he then assigned to it— 
Notornis, Struthio, Didus, Apteryx, Dinornis and Palapteryx, which last three he 
said “bear affinity to the Megapodial family of Gadling,” while he considered that 
“the Ostrich bears the same relation to the Bustards” as Notornis to the Coots! 
3 This doctrine, like that of the Correlation of Growth, is one that may be made 
to account so easily for many difficulties, otherwise apparently insuperable, that one 
is inclined always to view its application with suspicion, and to be loth to invoke its 
aid except on the greatest emergency. 
4 Quite recently Prof. Milne-Edwards (Ann. Sc. Wat. ser. 7, ii. p. 184) declares 
against the homogeneity of the “ Brévipennes,” and consequently admits the isomor- 
phism of some New-Zealand and Mascarene types. 
5 It is much to be regretted that while so many works of trifling importance are 
continually being reviewed in our scientific journals, Prof. Fiirbringer’s has obtained 
but little notice in this country. An excellent abstract by Dr. Gadow was published 
in Nature (xxxix. pp. 150-152, 177-181) for the 18th and 20th December 1888, and 
its republication in an accessible form would be most useful, since no translation of 
the original could be hoped for. A more condensed summary, with the author’s own 
paradigm, was given by Mr. A. H. Evans (Zool. Rec. xxv. Aves, pp. 14-16), while Dr. 
Sharpe (Attempts at Classif. B. pp. 39-43) has reproduced the original plates as well 
