Online Dictionary of Invertebrate Zoology: Complete Work - Best Text

Online Dictionary of Invertebrate Zoology 679behind the prostomium.perisympathetic system (ARTHRO: Insecta) Neurohemal organsconnected to the transverse nerves of the ventralsympathetic nervous system, that release the products ofthe neurosecretory cells in the ventral ganglia.peritoneal membrane see peritoneumperitoneal sheath (ARTHRO: Insecta) A network of anastomosingmuscle fibers that holds together the ovarioles ofthe ovary.peritoneum n. [Gr. peri, around; tonos, strain; eous, composedof] A thin serous membrane lining the body cavity;covering and supporting the organs. peritoneal a.peritreme n. [Gr. peri, around; trema, hold] 1. (ARTHRO: Chelicerata)In Acari, a concave plate surrounding a stigma(=spiracle). 2. (ARTHRO: Insecta) An annular sclerite surroundinga spiracle. 3. (MOLL: Gastropoda) see peristome.peritrophic membrane (ARTHRO) An extracellular sheath inwhich chitin is present, separating the apical surface of themid-gut that protects the gut cells from mechanical damagecaused by abrasive food particles; usually looseningfrom the mid-gut and remaining around the food, passingwith the feces.perivisceral a. [Gr. peri, around; L. viscus, entrail] Surroundingthe viscera.permanent haplometrosis (ARTHRO: Insecta) A colony that isfounded by a single female whose initial offspring are sterilefemales, then later towards the end of the annual cyclereproductives are produced. see temporary haplometrosis,functional haplometrosis.permanent hybrid Hybrid that maintains its heterozygosity bybalanced lethal factors in its genotype.permanent parasite A parasite living its entire adult lifewithin or on a host.permanent pleometrosis (ARTHRO: Insecta) In social Hymenoptera,the foundation of colonies through swarming. seeprimary pleometrosis.permesothyridid foramen (BRACHIO) A pedicle opening found