INTRODUCTION III 
Under the name Jmpennes we have a group of Birds, the PeNaurns, 
smaller even than the last, and one over which until lately systematists 
have been sadly at fault ; for, though we as yet know little definite as te 
their embryology, no one, free from bias, can examine any member of the 
group, either externally or internally, without perceiving how completely 
different it is from any others of the Carinate division. There is per- 
haps scarcely a feather or a bone which is not diagnostic, and nearly 
every character hitherto observed points to a low morphological rank. 
The title of an Order can scarcely be refused to the Impennes. 
The group known as Pygopodes has been often asserted to be closely 
akin to the Impennes, and we have seen that Brandt combined the two 
under the name of Urinatores, but of their essential difference there can 
now be no doubt, and indeed it is hard to look upon Pygopodes as a natural 
group, so many are the differences between the Podicipedidx or GREBES 
and Colymbidx1 or Divers, though recent morphologists agree to unite 
them, while the affinity of the Divers to the AuKs seems to be still more 
uncertain, and there appears to be ground for considering the Alcidzx to 
be much modified relatives of the Laridz, ‘These are points deserving 
of still more attention on the part of embryologists than they have 
hitherto received. Under the improperly applied name of Gavizw the 
Gulls and their close allies form a very natural section, but it probably 
hardly merits the rank of an Order more than the Pygopodes, for its 
relations to the large and somewhat multiform though very natural 
group Limicolz have to be taken into consideration.2 The Limicoline 
genera Dromas and Chionis have many points of resemblance to the 
Laridz ; and on the whole the proper inference would seem to be that 
the Limicolz, or something very like them, form the parent-stock whence 
have descended the Gaviz, from which or from their ancestral forms the 
Alcidx have proceeded as a degenerate branch. If this hypothesis be 
correct, the association of these three groups would constitute an Order, 
of which the highest Family would perhaps be Oftididx, the Busrarps, 
associated with the foregoing by Prof. Fiirbringer, but regarded by Dr. 
Gadow as allied to Cranes, Gruidx, and until further research shews 
which view can be maintained the matter must remain in doubt. On 
the other hand the Prrrets, which form the group 7'ubinares, seem for 
several reasons to be perfectly distinct from the Gulls and ener allies, and 
may be taken to rank as an Order. 
Considerable doubt had long been expressed as to the existence of an 
“Order” Alectorides, and it has just been stated that no one can now 
regard it as a natural group. One of the Families included in it by its 
founder is Cariamide (SmrteMA), the true place of which has been a 
puzzle to many systematizers. There is nothing, however, here to add to 
1 American ornithologists have lately used this term for the GREBES, to the great 
disturbance of nomenclature. It is apparently from the ancestors of the Oolymbide, 
before they lost their teeth, that Hesperornis branched off as a degenerate, bulky and 
flightless form. 
2 The late Prof. Parker long ago observed (Zrans. Zool. Soc. v. p. 150) that 
characters exhibited by Gulls when young, but lost by them when adult, are found 
in certain Plovers at all ages, and hence it would appear that the ‘‘Gavix” are but 
more advanced Limicola. : 
