A, Diagram of anterior extremity of an early embryo of "Scolopendra", ventral view; "cl", clypeus; "lb", labrum; "m", mouth; "p.a", preantennal appendage; "a", antenna; "int", premandibular rudiment; "mdl", mandible; "mx", maxilla; "p.g", palpognath; "t.g", toxicognath; "lg. 1", first pair of walking legs. B, Posterior end of a later embryo of "Scolopendra", ventral view, showing the anal segment or telson ("t"); the legs of the last pair in the adult ("lg. 21") and the two rudimentary pairs of legs ("lg. 22", "lg. 23"). Modified from Heymons, Bib. Zool., 1901, by permission of E. Nagele.