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 n.pl. [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 n.pl [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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