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The embryology of Geophilus by Metschnikoff shows plainly the four pairs of post-antennal appendages. The embryo Geophilus is hatched in the form of the adult, having, unlike the diplopods, no metamorphosis, its embryological history being condensed or abbreviated. But in examining Metschnikoff’s figures certain primitive diplopod features are revealed. The body of the embryo shortly before hatching is cylindrical; the sternal region is much narrower than in the adult, hence the insertions of the feet are nearer together, while the first six pairs of appendages begin to grow out before the hinder ones. Thus the first six pairs of appendages of the embryo Geophilus correspond to the antennæ, two pairs of jaws, and three pairs of legs of the larval Julus. These features appear to indicate that the chilopods may be an offshoot from the diplopod stem. The acquisition of a second pair of legs to a segment in diplopods, as in the phyllopod Crustacea, is clearly enough a secondary character, as shown by the figures of Newport in his memoir on the development of the Myriopoda (Pl. IV.). Thus the tendency in the Myriopoda, both diplopods and chilopods, is towards the multiplication of segments and the elongation of the body, while in insects the polypodous embryo has the three terminal segments of the abdomen well formed, these being, however, before hatching, partly atrophied, so that the body of insects after birth tends to become shortened or condensed. This indicates the descent of insects from ancestors with elongated polypodous hind-bodies like Scolopendrella. Korschelt and Heider suggest that the stem-form of myriopods was a homonomously jointed form like Peripatus, consisting of a rather large number of segments, but we might, with Haase, consider that the great number of segments which we now find indicates a late acquisition of this form.