. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. MYRIAPODA 415 followed by a preanal segment, the appendages of which are the cerci. On the anal segment appendages are vestigial. In the head, six pairs of coelomic sacs are formed, and in the abdomen each segment is provided with a single pair. The antennary and pre- antennary coelomic sacs together form the aorta. The coelomic sacs, from the mandibular segment backwards, grow through the yolk cells, enclo
. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. MYRIAPODA 415 followed by a preanal segment, the appendages of which are the cerci. On the anal segment appendages are vestigial. In the head, six pairs of coelomic sacs are formed, and in the abdomen each segment is provided with a single pair. The antennary and pre- antennary coelomic sacs together form the aorta. The coelomic sacs, from the mandibular segment backwards, grow through the yolk cells, enclosing part of these as mid-gut epithelium; they all furnish cardioblasts for the heart. The premandibular coelomic sac gives rise to a large excretory gland which degenerates at the time of eclosion; in association with it is a clump of nephrocytes, perhaps homologous with the sub- esophageal bodies of insects. The salivary gland is a remnant of the maxillary coelomic sac. The genital tubes arise by concrescence of the vestiges of the coelomic sacs from the fourth abdominal to the preanal segments. Vestigial coelomoducts survive in the preanal segment until after eclosion. The ganglia of the nervous system develop in association with "ven- tral organs" as in Peripatus. From the remnants of these organs the eversible sacs arise. References Onychophora: (Included here for convenience) Bouvier (1905). Euperipatus weldoni: Evans (1902). Peripatus sp.; Balfour (1883), Ryder (1886a), Willey (1898). P. capensis; King (1926), Mosely (1874), Sedgwick (1885-1888). P. edwardsi; Kennel (1886). P. imthurmi; Sclater (1886). P. novae-zealandica; Sheldon (1887). P. torquatus; Kennel (1886). Chilopoda: Heymons (18986); Verhoeff (1925). Geophilus sp.; Balbiani (1883), Leydig (1889), Metschnikoff (1874). G. ferrugineus; Zograf (1882, 1884). G. proximus; Zograf (1882, 1884). Lilhobius sp.; Leydig (1889). L. forficatus; Biegel (1922). Scolopendra sp.; Heymons (1898a), Nath and Husain (1926
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