title: [Interrelation between the sexual and digestive systems of chaetognaths (Chaetognatha)].
abstract: Histological and histochemical investigations on structure of the reproductive and digestive systems have been performed in two cold-water (Sagitta elegans, Sagitta maxima) and in four tropical (Sagitta bipunctata), Flaccisagitta hexaptera, Sagitta pulchra, Ferosagitta ferox) species of Chaetognatha. There is no essential seasonal difference in structure of the intestinal epithelial cells. There is not any storage of nutritional substances. Chaetognatha seem to feed actively during their whole life cycle. Some features of alimentary oogenesis have been revealed, although, in the whole, their ova mature according to the solitary type. At initial stages of oogenesis the nuclear apparatus is inactivated (condensed chromosomes form a ball--caryosphere); cells of the micropilar apparatus perform the function of the nutritive cells. The remaining period of oogenesis (synthesis of protein and lipid yolk) is performed according to the solitary type (the nucleoplasm contains chromosomes of the "lamp brush" type). A possibility whether nutritive substances can diffuse from the digestive tract into the coelomic fluid and into the ovarian cavity towards the developing ova is discussed.
mesh_terms: D000818:Animals; D004064:Digestive System / Q000033:anatomy & histology*; D005260:Female; D005835:Genitalia / Q000033:anatomy & histology*; D009866:Oogenesis; D010063:Ovum / Q000648:ultrastructure; D010933:Plankton / Q000033:anatomy & histology*; D012098:Reproduction; D013045:Species Specificity; D015048:Zooplankton / Q000033:anatomy & histology* / Q000254:growth & development / Q000378:metabolism
vernacular_title: K voprosu o vzaimosviazi polovoĭ i pishchevaritel'noĭ sistem shchetinkocheliustnykh (Chaetognatha).