Online Dictionary of Invertebrate Zoology: Complete Work - Best Text

Online Dictionary of Invertebrate Zoology 689zoa) In Siphonophora, a thick, gelatinous leaf-like or helmet-shapedmedusoid containing a simple or branchedgastrovascular canal, protective in function; a hydrophyllium;a bract.phylogeny n. [Gr. phyle, tribe; genesis, beginning] The studyof the history of the lines of evolution of a species or highergroup of organisms; distinguished from ontogeny. seeclassification. phylogenetic a.phylogerontic a. [Gr. phyle, tribe; gerontos, old man] Inphylogeny, referring to the decadence of the old age stage.see paracme, typolysis.phylogram n. [Gr. phyle, tribe; gramme, mark] A tree-likediagram indicating degree of relationship among taxa.phyloneanic a. [Gr. phyle, tribe; neanikos, youthful] Adolescentstage in phylogeny. see neanic.phylum n.; pl. phyla [Gr. phyle, tribe] One of the higher taxonomiccategories of the animal kingdom.physa n. [Gr. physa, bladder] (CNID: Anthozoa) The bulbousbase of burrowing Actinaria.physergate n. [Gr. physa, bladder; ergate, worker] (ARTHRO:Insecta) In Hymenoptera Formicidae, large workers capableof egg production, but mainly utilized for honey storage.physiogenesis n. [Gr. physis, nature; genesis, beginning]Differentiation of the embryo leading to distinctive differencesbetween and within regions. see histogenesis.physiology n. [Gr. physis, nature; logos, discourse] The studyof cell and tissue function and activities of living organisms.physogastry n. [Gr. physa, bladder; gaster, belly] (ARTHRO:Insecta) Swelling of the abdomen due to hypertrophy of fatbodies, ovaries, or both.phytoalexins n. [Gr. phyton, plant; alexein, to protect] Agroup of protective substances synthesized by plants as aresult of infection, thought to aid in resistance to nematodes,bacteria and environmental accidents.phytobiotic a. [Gr. phyton, plant; bios, life] Living withinplants.