aculeiform a. [L. dim. acus, needle; forma, shape] Formed like a thorn.
aculeus n.; pl. -lei [L. dim. acus, needle] (ARTHRO: Insecta) 1. In Hymenoptera, an ovipositor in the form of a sting. 2. In Diptera, a sharp spine projected from the margin of the eighth sternite of Tipulidae.
acumen n. [L. acumen, point] 1. (ARTHRO: Crustacea) In De-capoda, the pointed tip of the rostrum. 2. (ARTHRO: Insecta) The pointed tip of genitalia.
acuminate a. [L. acumen, point] Terminating in a long tapering point.
acuminose a. [L. acumen, point] Nearly acuminate.
acuminulate a. [L. acumen, point] Minutely acuminate.
acupunctate a. [L. acus, needle; punctus, a pricking] Pertaining to fine superficial punctures as if made with a needle.
acutangular a. [L. acutus, sharpened; angulus, angle] Forming or meeting at an acute angle.
acute a. [L. acutus, sharpened] Pointed; forming an angle of less than 90°; having a sharp or sharply tapering point. see obtuse.
acutilingual a. [L. acutus, sharpened; lingus, tongue] Having a sharp pointed tongue or mouth structure.
acutilingues n. pl. [L. acutus, sharpened; lingua, tongue] A former classification (Acutilinguae) of bees that have a short pointed tongue. see obtusilingues.
acyclic a. [Gr. a, without; kyklos, circle] Referring to noncyclic; not arranged in circles or whorls.
adactyl, adactyle a. [Gr. a, without; daktylos, finger] Lacking fingers, toes, or claws.
adambulacral a. [L. ad, near; ambulare, to walk] (ECHINOD: Asteroidea) Relates to structures situated along the ambu-lacral grooves in starfish.
adanal a. [L. ad, near; anus, anus] Pertaining to being located near the anus.
adanal bursa (NEMATA) Referring to a bursa not enclosing the tail terminus; leptoderan.
adanal copulatory papillae (nemata) Male adanal supplements, glandular or sensory.
adanale n. [L. ad, near; anus] (ARTHRO: Insecta) The fourth axillary sclerite of a wing.
adanal segment (ARTHRO: Chelicerata) In Actinotrichida Acari, segment XIV plus one of the paraproctal segments.
adanal supplements (NEMATA) Organs of secretion and attachment near the male anus.
adapertural a. [L. ad, near; apertura, opening] (MOLL: Gastropoda) Refers to being toward the shell aperture.
adapical a. [L. ad, near; apex, top] (MOLL: Gastropoda) Slightly oblique or along the axis toward the top.
adaptation n. [L. ad, near; aptus, fit] The process and condition of showing fitness for a particular environment, as applied to characteristics of a structure, function, or entire organism; also the process by which such fitness is ac quired.
adaptive a. [L. ad, near; aptus, fit] Capable of or showing adaptation.
adaptive divergence Evolutionary new forms from a common ancestry due to adaptation to different environmental conditions.
adaptive ocelli (ARTHRO: Insecta) Simple eyes or ocelli of most larvae. see stemmata, ocellus.
adaptive race A race that is physiologically, rather than morphologically, distinguished.
adaptive radiation Evolutionary diversification of members of a single phyletic line into a series of different niches or adaptive zones.
adaxial a. [L. ad, near; axis, axle] 1. Situated on the side of, or facing toward an axis. 2. (MOLL: Gastropoda) Inward toward the shell axis.
adcauline a. [L. ad, near; caulis, stalk] (CNID: Hydrozoa) Pertaining to polyps that bend towards, or are near to the common stem.
addendum n.; pl. -da [L. addere, to add] Something to be added; an addition, extension or supplement.
additive variance Gradation due to the average value of different genes.
addorsal a. [L. ad, near; dorsum, back] Near to, but not on the middle of the dorsum.
addorsal line (ARTHRO: Insecta) A longitudinal line between the dorsal and subdorsal line of caterpillars.
adduct v.t. [L. ad, near; ducere, to lead] To draw towards a median axis or plane, or one part toward another. see abduct.
adduction n. [L. ad, near; ducere, to lead] 1. Drawn toward or beyond the median line or axis. see abduction. 2. (ARTHRO: Insecta) In describing the movement of the legs, the movement of the coxa towards the body.
adductor n. [L. ad, near; ducere, to lead] A muscle that draws parts together or toward the median axis. see adductor muscles.
adductor coxae (ARTHRO: Insecta) The second muscle of the coxa.
adductor mandibulae (ARTHRO) The muscle that retracts or closes the mandible.
adductor muscles 1. Any muscle that adducts or bring parts into apposition. 2. (ARTHRO: Crustacea) In bivalves, muscles attached to the carapace that pull it to the body, or connect the carapace. a. In Barnacles, any transverse muscle, especially those attached to the scutum for closing the aperture. 3. (MOLL: Bivalvia) A single posterior or an anterior and posterior muscle connecting the two valves. a. In oysters, the crescent shaped "catch" muscle that holds the valves in a set position, or the "quick" muscle, the main opening and closure muscle.
adductor muscle scar (ARTHRO: Crustacea) In Ostracoda, an impression of the adductor muscles on the valve interior, serving for closure of valves.
adductor pit (ARTHRO: Crustacea) Depression on the inner surface of the scutum between the adductor ridge and the occludent margin for the attachment of the adductor muscle of certain barnacles.
adductor ridge (ARTHRO: Crustacea) In sessile barnacles, the linear elevation on the inner surface bounding the adductor pit on the tergal side.
adecticous a. [Gr. a, without; dektikos, able to bite] (ARTHRO: Insecta) Pertaining to pupae without articulated mandibles. see decticous.
adelocerous, adelaceratous a. [Gr. adelos, concealed; keras, horn] (ARTHRO: Insecta) Having antennae concealed in a cavity or groove.
adelocodonic a. [Gr. adelos, concealed; kodon, a bell] (CNID: Scyphozoa) Refers to degenerate attached medusae lacking an umbrella (bell).
adelomorphic, adelomorphous a. [Gr. adelos, concealed; morphe, form] Indefinite or obscure in form.
adelonymy n. [Gr. adelos, concealed; onymos, name] State of an organ that makes it impossible to receive a distinct no-menclatorial designation. adelonymous a.
adelphogamy n. [Gr. adelphos, brother; gamos, marriage] Mating of siblings. see back-cross.
adelphoparasite n. [Gr. adelphos, brother; para, beside; sitos, food] (ARTHRO: Insecta) A heteronomous hyperparasi-toid.
adendritic, adendric a. [Gr. a, without; dendron, tree] Having no dendrites or branches.
adeniform a. [Gr. aden, gland; L. forma, shape] Glandlike; resembling the shape of a gland.
adenine n. [Gr. aden, gland] A 6-amino-purine base, closely related to uric acid, that derived its name from the original source from which it was derived.
adenoblast n. [Gr. aden, gland; blastos, bud] An embryonic glandular cell.
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