Smithsonian miscellaneous collections . actile penis. In the Ana-morpha, which add segments during postembryonic development froma generative zone before the telson, the genital segments are the lastto be formed. The definitive segmentation of the chilopod body, there-fore, depends on the number of somites generated before the estab-lishment of the genital segments, after which there is no furthersomite propagation. The variable number of pregenital segmentsgenerated in the Chilopoda from a postgenital zone of growth, asalready noted, must lead to the conclusion that the two segments inthe def
Smithsonian miscellaneous collections . actile penis. In the Ana-morpha, which add segments during postembryonic development froma generative zone before the telson, the genital segments are the lastto be formed. The definitive segmentation of the chilopod body, there-fore, depends on the number of somites generated before the estab-lishment of the genital segments, after which there is no furthersomite propagation. The variable number of pregenital segmentsgenerated in the Chilopoda from a postgenital zone of growth, asalready noted, must lead to the conclusion that the two segments inthe definitive genital region are not homologous somites in all cases,notwithstanding their similarity of structure. However, the structureof these two segments is probably only that which any segments mighttake on if arrested in their growth at an early stage of development. The most generalized condition of the genital region in the adultchilopod is found in the Geophilomorpha, in which both genital sterna NO. 14 INSECT ABDOMEN SNODGRASS 55. ^ ^ gg-S Gpr
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Keywords: ., bookcentury1800, bookdecade1860, bookidsmiths, booksubjectscience
