tropis n. [Gr. tropus, keel] 1. (ARTHRO: Crustacea) In Ostra-cods, a heavy chitinous (or two unfused rods) connecting the zygum to the sternix and pastinum. 2. (NEMATA: Ade-nophorea) In Enoplida, a hollow tooth-like structure formed by a subventral wall of the buccal capsule.
tropism n. [Gr. tropos, turn] A movement, orientation or locomotion of a motile organism in response to a stimulus. a. Positive tropism: toward the stimulus. b. Negative tropism: away from the stimulus. see taxis.
tropotaxis n. [Gr. tropos, turn; taxis, arrangement] A type of taxis in which an animal directs itself in relation to a source of stimulation by comparing the amount of stimulation on either side of it, i.e., spiders in their web retrieving their prey. see klinotaxis, telotaxis.
trumpet n. [OF. trompe, trumpet] (ARTHRO: Insecta) In Diptera, paired, usually movable respiratory structures, located on the dorsal portion of the cephalothorax of culicid pupae. see laticorn trumpet, angusticorn trumpet.
truncate a. [L. truncus, cut off] Terminating abruptly; ending squarely with a cut-off edge. truncation n.
trunk n. [L. truncus, cut off] 1. (ANN) a. In Polychaeta, the body between the peristomium and the pygidium. b. In Oli-gochaeta, the body between the peristomium and pe-riproct. 2. (ARTHRO: Crustacea) The postcephalic portion of the body. 3. (ARTHRO: Insecta) The thorax.
trypsin n. [Gr. tryein, to rub down; pepsis, digestion] An enzyme that catalyzes the hydrolysis of proteins. tryptic a.
tryptophan, tryptophane n. [Gr. tryein, to rub down; pha-nein, to appear] An amino acid existing in proteins, from which it is set free by tryptic digestion, that gives a red or violet color on oxidation; it is essential to animal life.
T-tubule Invaginations of the plasma membrane into the muscle fiber between the Z- and H-bands.
tube n. [L. tubus, tube] Any hollow, cylindrical structure.
tube-feet (echinod) Small, fluid-filled tubes of the water vascular system functioning in locomotion, adhesion, food capture and transport to the mouth; some are sensory and may assist in respiration.
tubercle n. [L. dim. tuber, hump] 1. A small knoblike or rounded protuberance. see torus. 2. (ARTHRO: Insecta) In Diptera, sometimes used for an elongate facial swelling. tuberculate , tuberculose a.
tubercula pubertatis (ANN: Oligochaeta) A glandular swelling near the ventrolateral margin of the clitellum of mature adult earthworms during copulatory phase; differs in size, shape and continuity.
tuberiferous a. [L. dim. tuber, hump; fero, bear] Bearing tu bercles.
tube tracheae (ARTHRO: Chelicerata) In Opiliones, Solifugae and most spiders, tube-like tracheae; usually unbranched ectodermal invaginations. see sieve tracheae.
tubicolous a. [L. tubus, tube; colere, to dwell] Inhabiting a tube; a tubular spider web.
tubifacient a. [L. tubus, tube; facere, to make] Tube constructing.
tubulus n. [L. dim. tubus, tube] (ARTHRO: Insecta) In Lepi-doptera, a tubular, telescoping ovipositor.
tubus n. [L. tubus, tube] (NEMATA) A cuticular projection surrounding the spicules beyond the body outline; cloacal tubus.
tuft sensilla (ARTHRO: Crustacea) In Decapoda, small branched hairs over pores in the carapace with two or three attached neurons, functioning in vibration and water movement detectors.
Tullgren funnel Apparatus designed by A. H. Tullgren for extraction of animals from duff and litter; the sample is placed on a sieve and heat is applied from above to drive the animals downward into a funnel with a collecting vessel below; similar to a Baerman funnel that uses a water interface between sample and collecting vessel.
tumefaction n. [L. tumere, to swell; facere, to make] Abnormal tissue formations in invertebrates having characteristics in common with vertebrate neoplasms, however, precise nature is unknown.
tumescence n. [L. tumescere, to swell up] Slightly tumid or enlarged.
tumid a. [L. tumere, to swell] Swollen; enlarged; abnormally distended.
tumulus n. [L. tumulus, mound] (ARTHRO: Insecta) In Apis, a pile of earth at the mouth of an underground burrow.
tun n. [L. tunica, garment] (TARDI) A cryptobiotic shriveled, state of tardigrades produced by evaporation of surrounding water film.
tunic n. [L. tunica, garment] A covering membrane or tissue.
tunica n.; pl. -cae [L. tunica, garment] 1. A covering or enveloping membrane or tissue; a tunic. 2. (ARTHRO: Insecta) For Lepidoptera see diaphragm.
tunica adventitia Outermost fibro-elastic layer of various tubular organs, such as vas deferens, esophagus, uterus, ureter, etc.
tunica intima An inner lining or membrane.
tunica propria (ARTHRO: Insecta) In females, an elastic membrane, with or without fine fibrils, that encloses the ovariole and terminal filament.
tunicary a. [L. tunica, garment] Pertaining to a covering membrane or a tunic.
tunicate a. [L. tunica, garment] 1. Having a tunic. 2. (ARTHRO) Applied to coupling joint of antennae.
turbinate a. [L. turbo, a whirl] Top-shaped; nearly conical with a round base; turbiniform.
turbinate eye (ARTHRO: Insecta) In male Baetidae Ephemer-optera, eyes enlarged, divided into lower and outer pig-mented ovals and raised on a broad stalk, with larger upper and inner portion usually pale with large facets.
turgid a. [L. turgidus, swollen] Swollen; distended.
turreted a. [L. turris, a tower] Tower-shaped.
turriculate a. [L. dim. turris, tower] (MOLL: Gastropoda) Having an acutely conical spire comprised of numerous flattish whorls; turriform; turrited.
tychoparthenogenesis n. [Gr. tyche, change; parthenos, virgin; genesis, beginning] Unfertilized eggs that can occasionally, or accidentally, develop through parthenogenesis.
tylasters n. [Gr. tylos, knob; aster, star] (PORIF) A star-shaped spicule with a small center and knobbed rays.
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