seem to
try to prevent. I have seen a bird sometimes in his struggles fly a yard
or two straight upwards, the impulse forcing him backwards while he
struggles to go forwards."[34]

The Short-faced tumblers are an improved sub-race which have almost lost
the power of tumbling, but are valued for possessing some other
characteristics in an extreme degree. They are very small, have almost
globular heads, and a very minute beak, so that fanciers say the head of
a perfect bird should resemble a cherry with a barleycorn stuck in it.
Some of these weigh less than seven ounces, whereas the wild rock-pigeon
weighs about fourteen ounces. The feet, too, are very short and small,
and the middle toe has twelve or thirteen instead of fourteen or fifteen
scutellae. They have often only nine primary wing-feathers instead of
ten as in all other pigeons.

RACE VIII. _Indian Frill-back_.--In these birds the beak is very short,
and the feathers of the whole body are reversed or turn backwards.

RACE IX. _Jacobin_.--These curious birds have a hood of feathers almost
enclosing the head and meeting in front of the neck. The wings and tail
are unusually long.

RACE X. _Trumpeter_.--Distinguished by a tuft of feathers curling
forwards over the beak, and the feet very much feathered. They obtain
their name from the peculiar voice unlike that of any other pigeon. The
coo is rapidly repeated, and is continued for several minutes. The feet
are covered with feathers so large as often to appear like little wings.

RACE XI. comprises _Laughers_, _Frill-backs_, _Nuns_, _Spots_, _and
Swallows_.--They are all very like the common rock-pigeon, but have each
some slight peculiarity. The Laughers have a peculiar voice, supposed to
resemble a laugh. The Nuns are white, with the head, tail, and primary
wing-feathers black or red. The Spots are white, with the tail and a
spot on the forehead red. The Swallows are slender, white in colour,
with the head and wings of some darker colour.

Besides these races and sub-races a number of other kinds have been
described, and about one hundred and fifty varieties can be
distinguished. It is interesting to note that almost every part of the
bird, whose variations can be noted and selected, has led to variations
of a considerable extent, and many of these have necessitated changes in
the plumage and in the skeleton quite as great as any that occur in the
numerous distinct species of large genera. The form of the s