downwards and backwards beneath the larger posterior portion lying
behind the antennae, so that these appendages, approximated in the
middle line, project directly forwards from the margin of the head
formed by this retroversion of the labral area. The maxillae are short
and have no sensory organ; the palpognaths consist of four segments, and
the toxicognaths have their basal segments fused to form a single coxal
plate.

_Order 1. Geophilomorpha_.--Chilopods with a large and indefinite
number of somites, most of which are partially or completely divided
into a smaller anterior segment, represented by a pretergal and two
presternal sclerites, and a larger posterior segment bearing the
spiracles and legs. Spiracles are present upon all the leg-bearing
somites except the first and last; and the legs which are short and
subequal in length consist of six segments, the basal of which remains
small. There are no eyes, and the antennae consist invariably of
fourteen segments. The tergal plate of the somite bearing the
toxicognaths always remains distinct and separates the head-shield
from the tergum of the first leg-bearing somite. The penultimate and
antepenultimate segments of the toxicognaths are reduced on the
preaxial side of the appendage to the condition of arthrodial
integumental folds and suppressed on the postaxial side where the
distal segment or fang is firmly jointed to the femoral segment. In
the last leg-bearing somite the pleural sclerites coalesce with the
coxa of the appendage; but the second segment (trochanter) of this
appendage does not fuse with the third (femur). The genital and anal
somites are not retractile within the last leg-bearing somite, and the
gonopods typically persist in the male as small two-jointed appendages
and in the female as jointed or unjointed sclerites. The young are
hatched with the full number of segments.

[Illustration: FIG. 6. (After Latzel, _Die Myr. ost.-ung. Mon._ vol.
i. "Chilopoda," Vienna, 1880.)

A, Upper view of anterior extremity in _Geophilus_.

a, Basal segments of antennae.

c, Cephalic plate.

t.palp, Tergal plate of somite, bearing palpognaths.

t.tox, Tergal plate of somite, bearing toxicognaths (_tox_).

t.lg.1, Tergal plate of somite, bearing legs of first pair.

B, Toxicognaths of _Scolopendra_, showing the large coxal plate and
the reduced penultimate and antepe