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The structure of the head of centipedes is shown in part in Fig. 12, compare also Fig. 8. It will be seen that it differs much from that of the diplopods, though the mandibles (protomalæ) are homologous; they are divided into a cardo and stipes, thus being at least two-jointed.

The second pair of postoral appendages is in centipedes very different from the gnathochilarium of diplopods. As seen in Fig. 12 2, they are separate, cylindrical, fleshy, five-jointed appendages, the maxillary appendages of Newport, which are “connected transversely at their base with a pair of soft appendages” (c), the lingua of Newport. The third and fourth pair are foot-jaws, and we have called them malipedes, as they have of course no homology with the maxillipedes of Crustacea. The second pair of these malipedes, forming the last pair of mouth-appendages, is the poison-fangs (4), which are intermediate between the malipedes and the feet; Meinert does not allow that these are mouth-appendages.

Fig. 12.—Structure of a chilopod. A, Lithobius americanus, natural size. B, under side of head and first two body-segments and legs, enlarged: ant, antenna; 1, jaws; 2, first accessory jaw; c, lingua; 3, second accessory jaw and palpus; 4, poison-jaw. (Kingsley del.) C, side view of head (after Newport): ep, epicranium; l, frontal plate; sc, scute; 1, first leg; sp, spiracle.