Articulated apex see clasp filament

articulate fascia A band of contiguous spots.

articulation n. [L. articulare, to divide] A movable point of contact between two sclerotic parts of a structure.

artifact, artefact n. [L. ars, art; facere, to make] An appearance, or structure, produced by preparation of material that was not present in the original material before the manipulation.

artificial classification A classification based on convenient and conspicuous diagnostic characters, ignoring characters indicating relationship; often a classification based on a single character instead of an evaluation of all of the characters. see classification, phylogeny.

ascaridin, ascaridine n. [Gr. askaris, an intestinal worm] (NEMATA) A protein in the sperm.

ascarylic acid Material making up the refringent bodies or crystalloids in the oocytes of nematodes, that presumably form the vitelline membrane of the egg.

Aschelminthes, aschelminths [Gr. askos, bag; helmins, worm] A taxon (phylum) of the animal kingdom, when recognized, that includes the (classes) Rotifera, Gastrotricha, Kinorhyncha or Echinodera, Nematomorpha or Gordiacea, and Nemata (=Nematoda).

ascon n. [Gr. askos, bag] (PORIF) 1. A simple sponge with unfolded pinacoderm and choanoderm. 2. Sometimes used to describe the small, simple, most primitive sponge Leu-

cosolenia .

asconoid grade (PORIF) A grade of construction in which the choanocytes line thin, short tubes. see syconoid grade, leuconoid grade or type.

ascopore n. [Gr. askos, bag; poros, channel] (BRYO: Gymnol-aemata) In some Cheilostomata, a small opening in the frontal wall connecting the ascus to the external environment.

ascus n.; pl. asci [Gr. askos, bag] (BRYO: Gymnolaemata) In ascophoran cheilostomates, the exterior-walled, flexible-floored, sac beneath the frontal shield of an autozooid. see anascan.

ascus sac (MOLL: Gastropoda) In Sacoglossa, a storage area for the holder of outgrown teeth usually retained in a spiral or jumbled heap in the pharynx; ventral sac.

asemic a. [Gr. asemos, without mark] Pertaining to being without markings.

aseptate a. [Gr. an, without; L. septum, partition] Pertaining to being without a septa.

aseptic a. [Gr. an, without; sepsis, decay] Refers to being free of microorganisms, especially those causing decay, putrefaction, or poisoning.

aseptic culture A maintained population of organisms containing a single species and free of contamination by all other organisms.

asetal a. [Gr. an, without; L. seta, bristle] (ANN: Oligochaeta) Pertaining to being without setae; as in the peristomium and pygomere of earthworms.

asexual a. [Gr. an, without; sexus, sex] Not related to sex.

asexual reproduction Any method of reproduction not involving fertilization, as that by fission, fragmentation, spore production, budding, vegetative reproduction, and gemmule formation.

asiphonate a. [Gr. an, without; siphon, tube] Lacking a siphon.

aspect n. [L. aspicere, to look at] The general appearance, direction or view with respect to seasons, species or popula-

tions, an object or individual.

aspection n. [L. aspicere, to look at] Seasonal succession of ecological phenomena.

asperate a. [L. asperare, to roughen] Referring to having a rough and uneven surface.

asperity n.; pl. -ties [L. asperare, to roughen] 1. Roughness of surface. 2. (ARTHRO: Insecta) Spinelike structures arranged in rows or confined to specific areas; sculpturings or dotlike elevations.

asperous a. [L. dim. asper, rough] (MOLL) Used to denote very distinct elevated dots, more uneven than scabrous; rough to the touch.

asperulous a. [L. dim. asper, rough] Slightly rough.

asphyxia n. [Gr. an, without; sphyzein, pulse, respiration] Suffocation; suspended animation or apparent death resulting from a deficiency of oxygen. asphyxial a.

asphyxiation n. [Gr. an, without; sphyzein, pulse, respira-trion; L. -tion, denotes act] Act of causing axphysia; suffocation.

aspidium n. [Gr. aspidion, a little shield] A drug used for the expulsion of tapeworms obtained from male Dryopteris filix-mas ferns from which it is extracted as oleoresin of as-pidium.

aspidosoma n. [Gr. aspis, shield; soma, body] (ARTHRO: Cheli-cerata) In Acari, the dorsal region bordered laterally by the abjugal furrow that may be indistinct or incomplete, posteriorly by the disjugal furrow, and anteriorly by the circum-capitular furrows.

asplanchnic a. [Gr. an, without; splanchnon, entrail] Pertaining to the lack of an alimentary canal.

asporogenic a. [Gr. an, without; spora, seed; genes, producing] Pertaining to not producing or bearing spores. aspor-ous a.

assemblage n. [L. assimulare, to bring together] A collection of organisms, or particular things.

assembly n.; pl. -lies [L. assimulare, to bring together] An assemblage of organisms; the smallest community recog nized in ecology.

assimilation n. [L. ad, near; similis, like] The basic nature of living matter to convert other substances into its own components. see genetic assimilation.

association n. [L. ad, near; sociare, to join] 1. A group assemblage of organisms in a specific geological area with one or two dominant species. 2. A climax plant community dominated by a particular species and named according to their characteristics.

association neuron An internuncial neuron, that connects sensory and motor neurons, or other association neurons of the central nervous system; a connector neuron.

associes [L. ad, near; sociare, to join] 1. A transitory or intermediate stage in the development of an association. 2. A developmental unit of a consocies.

assortment n. [L. ad, near; sors, lot] 1. To distribute or classify. 2. The normal separation of genes at meiosis.

assurgent a. [L. assurgens, to arise] Curving upward; ascending.

astacene, astacin n. [L. astacus, lobster] A carotenoid red pigment of some invertebrates.

astaxanthin n. [L. astacus, lobster; xanthos, yellow] (ARTHRO) A carotenoid biochrome of certain ingested vegetation found in certain insects and marine crustaceans.

astegasimous a. [Gr. an, without; stege, roof] (ARTHRO: Che-licerata) Referring to mites when the prodorsal sclerite does not project over the chelicerae. see stegasimous.

astelocyttarous a. [Gr. an, without; stele, pillar; kyttaros, cell of a honeycomb] (ARTHRO: Insecta) Pertaining to nests, especially of social wasps, in which the brood comb is directly attached to a support and lacking pillars. see stelocyttar-ous.

aster n. [Gr. aster, star] 1. Star-shaped figures that develop during mitosis. 2. (PORIF) A type of microsclere with several rays originating from the same center. see chiaster.

asteriform a. [Gr. aster, star; forma, shape] Of or pertaining to starlike or star-shaped.

asteroid a. [Gr. aster, star; eidos, form] 1. Refers to starlike or resembling a star. 2. (ECHINOD) A stellate echinoderm of the subclass Asteroidea.

Asteroidea n. [Gr. aster, star; eidos, form] A subclass of So-masteroidea of the phylum Echinodermata, containing the stellate sea stars and star fish; characterized by having five-radiate to multi-armed rays, usually not sharply offset from the central disk.

asthenia n. [Gr. asthenes, feeble] Muscle weakness; debility.

asthenobiosis n. [Gr. asthenes, feeble; biosis, manner of life] (ARTHRO: Insecta) Hibernation or aestivation in certain generations of insects induced by non-elimination of uremic products by previous active generations.

astichous a. [Gr. an, without; stichos, row] Not arranged in a row or rows.

astigmatic a. [Gr. an, without; stigma, mark] Lacking stigmata; without a spiracle or breathing pore.

astogenetic differences (BRYO) Differences in the morphology of an asexual generation of zooids, and thereby restricted to zones of astogenetic change in the colony.

astogeny n. [Gr. asty, town; genos, descent] (BRYO) The development of a colony through a sequence of asexual generations of zooids with any extrazooidal parts.

astomate a. [Gr. a, without; stoma, mouth] 1. Lacking a mouth. 2. (ANN: Oligochaeta) In earthworms, a closed nephridium, without a nephrostome. 3. (NEMATA) Referring to a stoma lacking the cheilostome, but retaining an unex-panded esophastome.

astragal n. [Gr. astragalos, vertebra] (MOLL: Gastropoda) The step-sided, rounded elevations of a shell, that extend spirally around the whorls giving added strength.

astral ray 1. A ray seen in the cytoplasm that radiates from each centriole to the asters during cell division, thus forming the spindle. 2. A polar ray.

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