Gastral cavity see spongocoel

gastral groove (ARTHRO: Insecta) A longitudinal furrow in the mid-line of the ventral plate of some eggs.

gastralia n. [Gr. gaster, stomach] (PORIF: Hexactinellida) Mi-croscleres beneath the inner cell layer.

gastral layer or membrane (PORIF) Choanocytes lining the internal cavity.

gastral ray (PORIF) One of the quadriradiates embedded in the wall and projecting into the central gastral cavity.

gastric filament (CNID) A filament lined with nematocysts that kill living prey entering the stomach of a jellyfish.

gastric grooves (ARTHRO: Crustacea) In Stomatopoda, the longitudinal pair of grooves, extending from the base of the rostrum to the posterior margin of the carapace.

gastric mill (ARTHRO: Crustacea) 1. Thickened and calcified parts in the cardiac stomach lining composed of moveable articulated ossicles used to break up food. 2. In Acrotho-racica, chitinous triturating apparatus in the foregut; masticatory stomach.

gastric ossicles (ARTHRO: Crustacea) The teeth of the gastric mill.

gastric ostium (CNID) Gastric pouch opening of jellyfish.

gastric pouch (CNID) One of four enlargements of the stomach of a jellyfish.

gastric region (ARTHRO: Crustacea) In Decapoda, the median part anterior to the cervical groove and posterior to the frontal region.

gastric shield (MOLL: Bivalvia) A sclerotized plate that lines a part of the stomach, that aids the crystalline style by abrasion, thus releasing carbohydrate digesting enzymes.

gastric tooth (ARTHRO: Crustacea) In Decapoda, a tooth on the midline of the carapace anterior to the cervical groove.

gastrilegous a. [Gr. gaster, stomach; L. legere, to collect] (ARTHRO: Insecta) Pertaining to bearing pollen baskets beneath the abdomen.

gastrocoele n. [Gr. gaster, stomach; koilos, hollow] The gas-trulation cavity; archenteron.

gastrocoelus n.; pl. -li [Gr. gaster, stomach; koilos, hollow] (ARTHRO: Insecta) In Hymenoptera, transverse impressions at both sides of the base of the 2nd gastral tergite; includes thyridium.

gastrodermis n. [Gr. gaster, stomach; derma, skin] 1. A one cell thick lining of the digestive tract of coelenterates, ctenophors and platyhelminths. 2. Endoderm.

gastro-ileal fold (ARTHRO: Insecta) A circular valve-like fold separating the intestine and the chylific stomach or ventricle.

gastrolith n. [Gr. gaster, stomach; lithos, stone] (ARTHRO: Crustacea) In Decapoda, a discoidal calcareous nodule, commonly found in the stomodeum.

gastroorbital carina (ARTHRO: Crustacea) In Decapoda, a narrow carapace ridge extending posteriorly from the supraorbital spine; supraorbital.

gastroorbital groove (ARTHRO: Crustacea) In Decapoda, a short, longitudinal carapace groove branching from the cervical groove at the level of the orbit and directed toward it.

Gastropoda, gastropods n.; n.pl. [Gr. gaster, stomach; pous, foot] A class of asymmetrical univalve mollusks with stomach situated in the region of the foot, shell in one piece, often spirally coiled, that live in the sea, fresh water, and on land, and are either herbivorous or carnivorous.

gastropores n. [Gr. gaster, stomach; poros, hole] (CNID: Hy-drozoa) In Milleporina and Stylasterina, the larger pores in the coenosteum through which gastrozooids protrude.

Gastrotricha, gastrotrichs n.; n.pl. [Gr. gaster, stomach; thrix, hair] A phylum of aquatic micrometazoans that are oblong, strap-shaped to ovoid tenpin-shaped and bear locomotor cilia on the flattened venter.

gastrovascular cavity A body cavity in which functions of both digestion and circulation occur.

gastrovascular system The digestive-excretory system with out-pouchings and canals.

gastrozooid n. [Gr. gaster, stomach; zoon, animal] (CNID: Hy-drozoa) In some colonial cnidarians, a hydroid modified for feeding and digestion, also called siphons; in most species, they fulfill the defensive functions of the colony. see dac-tylozooid.

gastrula n. [Gr. dim. gaster, stomach] Embryonic stage resembling a sac with an outer layer of epiblastic cells (ectoderm) and an inner layer of hypoblastic cells (endoderm and mesoderm); the enclosed cavity is the archenteron or gastrocoel. gastrular a.

gathering hairs (ARTHRO: Insecta) The small hairs covering the glossa and the fringe of stouter bristles on the labellum of bees.

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