hydroecium n. [Gr. hydor, water; oikos, house] (CNID: Hydrozoa) A sheath-like extension that protects the zone of the siphonophoran bell from adjacent bells.
hydrofuge n. [Gr. hydor, water; L. fugere, to flee] (ARTHRO: Insecta) 1. Water repelling hairs. 2. The outer surface of the chorion of eggs, as well as the cuticles, respiratory siphons and hairs.
hydroid n. [Gr. hydor, water; eidos, like] (CNID) Polyp of coe-lenterates; any member of the Hydroida.
hydrolysis n.; pl. -es [Gr. hydor, water; lyein, to dissolve] Reaction of water with substances to produce simpler compounds as starch reduction to sugars or with inorganic compounds to produce acid, basic or neutral reactions in solution.
hydrophanous a. [Gr. hydor, water; phanerus, visible] Becoming transparent when immersed in water.
hydrophile hair (ARTHRO: Insecta) A water-attracting hair as opposed to a hydrophobe hair.
hydrophilous a. [Gr. hydor, water; philein, to love] Moisture-loving; hygrophilous.
hydrophobe hair (ARTHRO: Insecta) A hair with resistance to wetting, thus making a 90° angle of contact with the water surface. see hydrophile hair.
hydrophyllum n.; pl. -lia [Gr. hydor, water; phyllon, leaf] (CNID: Hydrozoa) A thick, gelatinous, helmet-shaped or leaf-like medusoid containing a simple or branched gas-trovascular canal, protective in function; a phyllozooid; a bract.
hydrophyton n. [Gr. hydor, water; phyton, plant] (CNID: Hy-drozoa) A hydroid colony complete with root-like organ, stem and branches.
hydroplanula n. [Gr. hydor, water; L. dim. planus, flat] (CNID) Larval stage between the planula and actinula larval stages.
hydropolyp n. [Gr. hydor, water; F. polype, polyp] (CNID: Hy-drozoa) A single polyp of a hydroid colony. see hydrula.
hydropore n. [Gr. hydor, water; poros, hole] (ECHINOD) In some modern larvae and some extinct forms, the opening into the left axocoel anterior to the hydrocoel, i.e., the canal extending from the axocoel to the surface.
hydropyle n. [Gr. hydor, water; pyle, orifice] (ARTHRO: In-secta) A specialized structure of an egg for the uptake of water; the thickened region of the serosal epicuticle over a layer of endocuticle, thinner than elsewhere.
hydrorhiza n. [Gr. hydor, water; rhiza, root] (CNID: Hydrozoa) A tubular or ribbon-like basal attachment of a colony anchoring the colony to the substrate; the stalk of the colony.
hydrosere n. [Gr. hydor, water; serere, to join] A sere originating in water. see lithosere, xerosere.
hydrosome (=hydrosoma) a. [Gr. hydor, water; soma, body] (CNID) A hydra-like stage.
hydrosphere n. [Gr. hydor, water; sphaira, ball] Aqueous envelope of the earth.
hydrospire n. [Gr. hydor, water; L. spira, coil] (ECHINOD) In extinct Blastoidea, respiratory structures in the form of pouches at the side of the ambulacral grooves.
hydrostatic a. [Gr. hydor, water; statikos, cause to stand] 1. Of or pertaining to the pressure of water. 2. (ARTHRO: In-secta) Pertains to floats, as air sacs in larval aquatic insects.
hydrostatic organs (ARTHRO: Insecta) In some larval Culici-dae, pigmented, crecent-shaped organs found laterally on the thorax and near the tail.
hydrostatic system (BRYO: Gymnolaemata) A method of protrusion of the lophophore in some autozooids; made up of flexible frontal wall or infolded frontal wall sac and attached parietal muscles which contract and raise the lophophore by hydrostatic pressure in the autozooid.
hydrostome n. [Gr. hydor, water; stoma, mouth] (CNID: Hy-drozoa) The mouth of a polyp.
hydrotaxis n. [Gr. hydor, water; taxis, arrangement] A taxis in response to a moisture gradient initiating stimulus.
hydrotheca n. [Gr. hydor, water; theke, case] (CNID: Hydro-zoa) Peridermal cups into which most or all of the hydranth can retract, may be provided with an operculum; in some Thecata, the cup may be reduced to a mere platform supporting the hydranth.
hydrotropism n. [Gr. hydor, water; tropos, turn] The response of an organism to water stimulus.
Hydrozoa, hydrozoans n.; n.pl. [Gr. hydor, water; zoon, animal] Class of the phylum Cnidaria having both polyp and medusal stages.
hydrula n. [Gr. hydor, water] A simple hypothetical polyp. see hydropolyp.
hygric a. [Gr. hygros, wet] Tolerating or being adapted to humid conditions.
hygrokinesis n. [Gr. hygros, wet; kinesis, movement] Orientation due to differences in humidity.
hygrometabolism n. [Gr. hygros, wet; metabole, change] The influence on metabolism by humidity.
hygropetric a. [Gr. hygros, wet; petros, stone] Pertaining to the fauna of submerged rocks.
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