April 1863. See also De Blainville 'Osteographie' page 128 for various
authorities on this subject.) the structure of the feet; in both front and
hind feet the distal phalanges of the two greater toes are represented by a
single, great, hoof-bearing phalanx; and in the front feet, the middle
phalanges are represented by a bone which is single towards the lower end,
but bears two separate articulations towards the upper end. From other
accounts it appears that an intermediate toe is likewise sometimes
superadded.

(FIGURE 4. OLD IRISH PIG, with jaw appendages. (Copied from H.D. Richardson
on Pigs.))

Another curious anomaly is offered by the appendages, described by M.
Eudes-Deslongchamps as often characterizing the Normandy pigs. These
appendages are always attached to the same spot, to the corners of the jaw;
they are cylindrical, about three inches in length, covered with bristles,
and with a pencil of bristles rising out of a sinus on one side: they have
a cartilaginous centre, with two small longitudinal muscles they occur
either symmetrically on both sides of the face or on one side alone.
Richardson figures them on the gaunt old "Irish Greyhound pig;" and
Nathusius states that they occasionally appear in all the long eared races,
but are not strictly inherited, for they occur or fail in animals of the
same litter. (3/25. Eudes-Deslongchamps 'Memoires de la Soc. Linn. de
Normandie' volume 7 1842 page 41. Richardson 'Pigs, their Origin, etc.'
1847 page 30. Nathusius 'Die Racen des Schweines' 1863 s. 54.) As no wild
pigs are known to have analogous appendages, we have at present no reason
to suppose that their appearance is due to reversion; and if this be so, we
are forced to admit that a somewhat complex, though apparently useless,
structure may be suddenly developed without the aid of selection.