MYRIA:PODA (Gr. myriad-footed), a class of Artieulakt, resembling Aunclida In their lengthened form, and in the great number of equal, or nearly equal, segments of which the body is-composed; but in most of their other characters more nearly agreeing insects, among which they were ranked by the earlier naturalists, and still are by some. They have a distinct head, but there is no distinction of the other segments, as In insects. into thorax and abdomen. They have simple or compound eyes; a few are destitute of eves. They have antennee like those of insects. The mouth is furnished with it complex masticating apparatus, in some resembling that of some insects in a larval state, in others, similar to that of crustaceans. Respiration is carried on through minute pores or spiracles, placed on each side along the entire length of the body, the air being distributed by innumerable ramifying air-tubes to all parts. In most parts of their internal organization the myriapoda resemble insects; although a decided infe. minty is exhibited. particularly in the less perfect concentration of the nervous sys tem. The resemblance is greater to insects in their larval than in their perfect state. The body of the myriapoda is protected by a hard chitinous covering. The number of seg ments is various, seldom fewer than 21; although in some of the higher genet-a they are consolidated together in pairs, so that each pair, unless closely examined, might be considered as one segment bearing two pairs of feet. The legs of some of the lower kinds, as Judas (q.v.) are very numerous, and may be regarded as intermediate between the appendages which serve many annelids as organs of locomotion, and the distinctly articulated legs of insects. In the higher myriapoda, as Scolopendra, the legs
are much fewer, and articulated like those of insects, - None of the Jnyriapoda have Some of thttn fell on Airganie, matter, •chiOly vegetable; those of higher organization are carnivorous. The myria, Dia do not undergo changes so great as those of insects, but emerge from the egg more similar to what they are ultimately to become; although some of them are at first quite destitute of feet; and, contrary to what takes place in insects, the body becomes more elongated as maturity is approached, the number of segments and of feet increasing.
The nivriapoda are divided into two orders: the lower, Chilognatha (Jules, etc.), hav ing the body sub-cylindrical, the feet very numerous, the head rounded, the mandibles thick and strong; the higher Chilopoda (Scolopendra, etc.), having the body flattened, the feet comparatively few, the head broad, the mandibles sharp and curved.
s The myriapoda are found in all parts of the world, in the ground, among moss, under stones, in the decaying bark of trees, in debaying roots, and in many similar. situations. The largest species are tropical. They are all generally regarded with aversion. It is doubtful how far any of them are injurious to crops, although it is not improbable that they accelerate rottenness already begun; but some (Centipedes) have a venomous and painful bite.