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14 HEAD, NECK, BODY. 
§ 31. Heap has the general shape of a 4-sided pyramid; of which the 
base is applied to the end of the neck, and does not appear from the exte- 
rior; the uppermost side is more or less convex or vaulted, sloping in every 
direction, and tapering in front; the sides proper are flatter, more or less 
perpendicular, and taper in front; the bottom is likewise flattish and simi- 
larly tapering. The departures from this typical shape are endless in degree, 
and variable in kind; they give rise to numerous general descriptive terms, 
as “head flattened,” “head globular,” ete., but these are not susceptible of 
precise definition. The sides present each two openings, eyes and ears; 
their position is variable, both absolutely and in respect to each other. But 
in the vast majority of birds, the eyes are strictly /ateral, and near the mid- 
dle of the side of the head, while the ears are behind and a little below. 
Exceptions :—owls have eyes “anterior ;” woodcock and snipe have ears be- 
low and not behind the eyes. The mouth is always a horizontal fissure in 
the apex of the cone; there are no other openings in the head proper, for 
the nostrils are always in the bill. The 
§ 32. Neck, in effect, is a simple cylinder: rendered somewhat hour- 
glass shaped as above stated. Its length is variable, as is the number of 
bones it has. Bearing the head with the bill, which is a bird’s true hand, it 
is unusually flexible, to permit the necessarily varied motions of this impor- 
tant organ. Its least length may be said to be that which allows the point 
of the bird’s beak to touch the oil-gland on the rump; its length is usually 
in direct proportion to length of legs, in obvious design of allowing the 
beak to touch the ground easily to pick up food. Its habitual shape is a 
double curve like the letter S; the lower belly of the curve fits in the space 
between the legs of the merry-thought (furcula) ; the upper limb of the 
curve holds the head horizontal. This sigmoid flexure (sigma, Greek S) is 
produced by the shape of the jointing surfaces of the several bones: it may 
be increased, so that the upper end touches the lower belly; may be de- 
creased to a straight line, but is scarcely carried beyond this in the opposite 
direction. As a generalization, the neck may be called longest in wading 
birds; shortest in perching birds; intermediate in swimming birds; but 
some waders, as plovers, have short necks; and some swimmers, as swans, 
extremely long ones; a very long neck, however, among perching birds is 
rare, and confined mainly to a crane-like African hawk, and certain of the 
lowest perchers that stand on the confines of the waders. The shape of the 
§ 33. Bopy proper or trunk (L. ¢runcus), is obviously referable to that 
of the egg; it is ovate, (LL. ovum, an egy). The swelling breast muscles 
represent the but of the egg, which tapers backwards. But this shape is 
never perfectly expressed, and its variations are unnumbered. In general, 
perching birds have a body the nearest to an oval; among waders, the oval 
is usually compressed, or flattened perpendicularly, as is well seen in the 
heron family, and still better in the rail family, where the narrowing is at 
an extreme; among swimmers, the body is always more or less depressed, 
or flattened horizontally, and especially underneath, to enable these birds to 
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