346 MR. W. K. PARKER ON THE OSTEOLOGY OF BAL/ENICEPS REX. 
teach us what licence may be taken with the shape of the jaws for special reasons in the 
life of the bird, whilst the general structure is quite normal. In the Scansorial and 
Insessorial Orders (so potent in families, genera, and species), we are scarcely surprised 
at anything we meet with as to the form of the jaws and consequent modification of the 
structure of the outworks of the cranium. Seeing how many genera and species there 
are with such modifications of the jaws and cranium as we meet with in the Parrot 
group, the Woodpeckers, the Toucans and Aracaris, the King-fishers, the Hornbills, and 
the Humming-birds, we can scarcely forbear supposing that numberless links have 
been lost amongst the Grall@ and Palmipeds'. Looking at the Totipalmate family of 
the latter order, what great gulfs intervene between the Pelicans and the Cormorants, 
and respectively between the Gannet, Frigate-bird, and Tropic-bird (Phaéton)! With 
regard to Pelicans, Cormorants, and Gannets, their structure is certainly essentially the 
same, and can be confounded with no other group whatever ; yet what a number of 
species, generic groups of species, ought to intervene between Pelecanus and Phalacro- 
corax, and between the latter and Sula! Nature is still more silent as to how she con- 
nected the Flamingos with the Geese: one of the links indeed has been found at the 
Goose end of this great gap, the Cereopsis Nove Hollandiz ; but where are the others ? 
Then, if these were found, we have to run up a long chain of forms between the Heron 
and the Flamingo; and we scarcely possess a link. Again, the great embryo-shaped 
reptilian Ostriches are only like a few widely distinct species belonging to family after 
family lost and gone for ever from the earth. 
Compared with the paucity of species of the Ostrich group, the numbers without 
number of Corvine, Passerine, and Sylviine birds are truly wonderful; and all these 
families, with many more, have the same essential structure. It would require many a 
genus, each with its suite of species, to connect together, in the way the Passerine birds 
are connected together, the different members of the Ardeine group, especially if we 
include Ciconia, Mycteria, and Anastomus. Nevertheless the typical Herons (e.g. Ardea, 
Botaurus, Nycterodius, and Egretta) are rather numerous ; and the modifications that have 
taken place in the Boat-bill and the Baleniceps do not at all affect the essential struc- 
ture of these birds ; these modifications may all be put down to the score of teleology. 
A certain similarity has been mentioned between the structure of the Baleniceps, and 
that of the Pelican ; but these are not relational modifications ; and no arguments can be 
brought to prove the Balzeniceps to be a Pelican but would almost equally serve to prove 
it to be a Parrot, a Serpentarius, or a Podargus. 
If all the birds that have been, could be seen side by side with those that now are, it 
would be a goodly sight ; no gaps to leap over, no missing links. Our knowledge of 
these things is in ‘ shreds and patches’; but still we can imagine that He who provided 
* Whether this net-work of affinities owes its present incompleteness to losses of the past, or is to be filled up 
by future creations, it is after all impossible for us to determine. On the question of the potency of genera and 
species, see an admirable paper by the late Hugh E. Strickland, Ann. and Mag. Nat. Hist., Nov. 1840, p. 184. 
