44 AFFINITIES [PART I.
demonstrative of its affinity to the Columbida, and of its remoteness from the Raptorcs. But
as these will form the subject of the second part of this work, and will there be treated in full
detail by Dr. Melville, I will only briefly enumerate the more important ones. These are:—
IS, the absence or non-developincnt of the vomer, and of the bony septum of the nostrils;
19, the long narrow nasal fissures; 20, the form of the posterior facet of the lower jaw ¡ 2 1 , the
oblique direction of the zygomatic bone; 22, the peculiar form of the palatine bones; 23,
the mesial occipital foramen above the foramen magnum, (peculiar, it woidd seem, to the
Pigeons and the Dodo); 24, the breadth and peculiar twist of the metatarsal of Ihe hind toe
(see Plate XI.); 25, the oval transverse section of the tarso-mctarsal; 26, the peculiar form
of the upper extremity of the tarso-metatarsal, including the arrangement of the calcaneal
processes, and of the canals for the passage of the flexor tendons; and 27, the fact (peculiar
to the Pigeons and the Dodo) that these canals pass on the outside of the posterior ridge of
the tarsus, and not on the inside, as in Gallinaceous buds.
Such are the principal points of agreement between the Dodo and the Pigeon family,
and it will be admitted that they are neither few nor trivial. There are, however, two or
three points of diversity which it is only fair to mention.
1. I need only allude as a matter of form to the non-development of wings, as it is admitted on
all hands that this character distinguishes the Dodo from all other birds with which it can be legitimately
compared, and is as much opposed to the normal structure of the Eapacious birds, as to that of
the Cohimbida.
2. The small size of t h e cranium in proportion to the beak distinguishes the Dodo no less from
the Pigeons than from the Vultures. This peculiarity results from the small relative dimensions of the
brain and eyes. It is a general law that animals of great magnitude (the Elephant and Whale, for
instance,) do not require those important organs to be enlarged in the same proportion as the parts
destined for locomotion, and the nutritive functions.1 We need not, therefore, wonder that so colossal
a bird as the Dodo should differ in tins respect from other members of that family to which it is nearest
allied.
3. The Dodo is, as Professor Owen remarks, " peculiar among birds for the equality of length of
the metatarsus and proximal phalanx of the hind toe," while in most birds lliis phalanx is considerably
longer than t h e metatarsal which supports it. The fact is, however, that no argument as to t he
general affinities of a doubtful ornithic genus can be drawn from the relative proportions of the tarsometatarsal,
the posterior metatarsal, and the proximal phalanx; these proportions varying in each
genus according as its habits are more or less cursorial, ambulatory, or insessorial. A glance at
Plate XL, where the forms of these bones in five different genera of Pigeons are exliibited, will substantiate
this remark.
4. And, lastly, the nostril of the Dodo, although agreeing in position with that of Treron, is of a
1 This law is probably based on the distinction between ponderable and imponderable substances. The bones
and muscles of an animal are mechanical structures, the size of which bears an exact arithmetical relation to the
masses which they arc required to move; but the eye and the brain have to deal with light and the nervous lluid—
imponderable agents, to which the ordinary laws of mechanics do not apply.
Cn. I.] OF T H E DODO. 45
different form, being slightly oblique upwards and backwards, while that of Treron is more horizontal.
This difference, however, is not greater than what prevails in the nostrils of other genera of pigeons.
It appears then, that the only points in which the Dodo can be said to differ materially
from the type of the Pigeons, are few in number, and are not such as to make any approximation
to the Raptorial form; and I think it will be granted that the numerous and important
characters which have been above noticed, will warrant us in regarding the genus Didus as a
very aberrant member of the family Columbidos.
Postscript 1.—At pp. 25, 3 3 , supra, I have inadvertently spoken of " t h e Gottorf Museum at Copenhagen."
At the time when Olearius published his catalogue, this collection was not at Copenhagen, but at
Gottorf, the seat of the Dukes of Scldeswig; whence it was removed by Frederic IV., about 1720, to
Copenhagen, and was incorporated with the Eoyal " Kunstkammer " in that metropolis.
2. It has been suggested to me that translations of the Latin, French, Dutch, and German passages,
extracted above (pp. 9-25), would be acceptable to many readers, and these are therefore given in the
Appendix.