The _nervous system_ differs considerably from that in the Order Chilognatha; it resembles that in the Schizotarsia, and differs again from that in the other two Orders, Symphyla and Pauropoda. The brain shows some differences from other Orders chiefly in the development of the different lobes which are connected with the sense organs, the eyes and antennae, for instance; but the most marked difference is in the ventral ganglionic cord. First, the ganglionic swellings are much more clearly marked than in the Chilognatha. Secondly, the first three ganglia differ {59}from the others in being nearer to one another and forming a single mass when seen by the naked eye, though when examined by the aid of a microscope we can see all the different parts are there. Thirdly, the division into two cords mentioned in the Chilognatha is carried to a much greater extent. The ganglia in each segment can be seen plainly to be double, and the cords connecting the ganglia are two in number. We can plainly see that the ventral nervous system of the Chilopoda consists of two cords lying parallel to one another, and each having a ganglionic enlargement in every segment. Whether a visceral nervous system is present in the group is doubtful. The eighth family of the Chilognatha, the Polyxenidae, show an approach to the Chilopod nervous system. The generative system differs chiefly in the opening of the genital apparatus at the end of the body instead of in the third segment; though this difference only separates the Order from the Chilognatha and not from the other Orders. They also have two pairs of large accessory glands (as they are called) connected with the genital openings. ORDER III. SCHIZOTARSIA. The third Order of Myriapods, the Schizotarsia, show a much greater resemblance to the Chilopoda than to the first Order, the Chilognatha. There are, however, important differences to distinguish them from all the other Orders. The shape of the body is short, thick, and very compact. The composition of the individual segments resembles that found in Chilopoda rather than that of Chilognatha. The antennae are very long, longer than in any of the Chilopods, and are composed of a great number of very small joints. The mouth parts show a greater length and slenderness than do those of the other Orders mentioned as yet. They consist of— 1. An _upper lip_ partly free, but fused at the sides with the rest of the head. The upper lip is in three parts, as in the Chilopoda, but with the middle part very small and the lateral pieces large. 2. A pair of _jaws_ or _mandibles_. These are provided not only with teeth, as in the other Myriapods, but also with a sort of comb of stiff bristles. {60}3 and 4. Two pairs of _maxillae_ or foot jaws distinguished by their length and slenderness. 5. The _poison claws_ long, slender, and not sharply curved. The bases of the poison claws hardly fused together and short.